Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Review Article
  • Published:

The development of nociceptive circuits

Key Points

  • Newborn infants show strong pain behaviour, but the nature of this pain is poorly understood and has, historically, been undertreated. The study of the development of nociceptive pathways shows that infant pain involves functional signalling pathways that are not found in the mature nervous system of healthy individuals. This review focuses on the underlying organization and strengthening of nociceptive circuitry in the dorsal horn during the first postnatal weeks and shows how this circuitry might be altered by sensory inputs in early life.

  • Peripheral and central nociceptive neurons are specified early in development, and recent studies have identified key molecular pathways that control their genesis. Neurotrophins, normally noted for their role in sensory neuron survival, are now known to affect almost every aspect of peripheral nociceptor development well into postnatal life.

  • A combination of pathway tracing and synaptic and systems electrophysiology has provided a picture of the formation of early sensory circuits in the developing dorsal horn of the spinal cord, and their ability to process nociceptive and non-nociceptive information.

  • In many respects, newborn sensory circuits are more excitable than their mature counterparts and receptive fields gradually become tuned during the postnatal period. There is evidence to indicate that this tuning arises from the refinement of afferent excitatory inputs and the maturation of inhibitory processes, both locally and descending from the brainstem.

  • The activity-dependence of excitatory and inhibitory synaptic maturation in the dorsal horn has been a recent focus of research, along with increasing evidence for the ability of both non-noxious and noxious sensory activity to influence the development of pain processing. The mechanisms by which early tissue damage and inflammation might affect future pain processing are discussed in this review.

  • The study of developing nociceptive pathways can be translated into an increased understanding of paediatric pain. Such research should help us to design better strategies for the relief of pain in infants and children.

Abstract

The study of pain development has come into its own. Reaping the rewards of years of developmental and molecular biology, it has now become possible to translate fundamental knowledge of signalling pathways and synaptic physiology into a better understanding of infant pain. Research has cast new light on the physiological and pharmacological processes that shape the newborn pain response, which will help us to understand early pain behaviour and to design better treatments. Furthermore, it has shown how developing pain circuitry depends on non-noxious sensory activity in the healthy newborn, and how early injury can permanently alter pain processing.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Neurotrophins and nociceptor development.
Figure 2: Reflex modules and nociceptive responses in neonates.
Figure 3: Schematic diagram of the synaptic changes that take place in the superficial laminae of the dorsal horn over the first 2–3 postnatal weeks.
Figure 4: Activity-dependent development in spinal cord sensory connections.

Similar content being viewed by others

References

  1. Zirlinger, M., Lo, L., McMahon, J., McMahon, A. P. & Anderson, D. J. Transient expression of the bHLH factor neurogenin-2 marks a subpopulation of neural crest cells biased for a sensory but not a neuronal fate. Proc. Natl Acad. Sci. USA 99, 8084–8089 (2002).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Altman, J. & Bayer, S. A. The development of the rat spinal cord. Adv. Anat. Embryol. Cell Biol. 85, 1–164 (1984).

    Article  CAS  PubMed  Google Scholar 

  3. Kitao, Y., Robertson, B., Kudo, M. & Grant, G. Neurogenesis of subpopulations of rat lumbar dorsal root ganglion neurons including neurons projecting to the dorsal column nuclei. J. Comp. Neurol. 371, 249–257 (1996).

    Article  CAS  PubMed  Google Scholar 

  4. Maro, G. S. et al. Neural crest boundary cap cells constitute a source of neuronal and glial cells of the PNS. Nature Neurosci. 7, 930–938 (2004).

    Article  CAS  PubMed  Google Scholar 

  5. Ma, Q., Fode, C., Guillemot, F. & Anderson, D. J. Neurogenin1 and neurogenin2 control two distinct waves of neurogenesis in developing dorsal root ganglia. Genes Dev. 13, 1717–1728 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Kirstein, M. & Farinas, I. Sensing life: regulation of sensory neuron survival by neurotrophins. Cell. Mol. Life Sci. 59, 1787–1802 (2002).

    Article  CAS  PubMed  Google Scholar 

  7. Coggeshall, R. E., Pover, C. M. & Fitzgerald, M. Dorsal root ganglion cell death and surviving cell numbers in relation to the development of sensory innervation in the rat hindlimb. Brain Res. Dev. Brain Res. 82, 193–212 (1994).

    Article  CAS  PubMed  Google Scholar 

  8. Jackman, A. & Fitzgerald, M. Development of peripheral hindlimb and central spinal cord innervation by subpopulations of dorsal root ganglion cells in the embryonic rat. J. Comp. Neurol. 418, 281–298 (2000).

    Article  CAS  PubMed  Google Scholar 

  9. Reynolds, M. L., Fitzgerald, M. & Benowitz, L. I. GAP-43 expression in developing cutaneous and muscle nerves in the rat hindlimb. Neuroscience 41, 201–211 (1991).

    Article  CAS  PubMed  Google Scholar 

  10. Mirnics, K. & Koerber, H. R. Prenatal development of rat primary afferent fibers: II. Central projections. J. Comp. Neurol. 355, 601–614 (1995).

    Article  CAS  PubMed  Google Scholar 

  11. Fitzgerald, M. Prenatal growth of fine-diameter primary afferents into the rat spinal cord: a transganglionic tracer study. J. Comp. Neurol. 261, 98–104 (1987).

    Article  CAS  PubMed  Google Scholar 

  12. Scott, S. A. The development of the segmental pattern of skin sensory innervation in embryonic chick hind limb. J. Physiol. (Lond.) 330, 203–220 (1982).

    Article  CAS  Google Scholar 

  13. Wang, G. & Scott, S. A. Development of 'normal' dermatomes and somatotopic maps by 'abnormal' populations of cutaneous neurons. Dev. Biol. 251, 424–433 (2002).

    Article  CAS  PubMed  Google Scholar 

  14. Keller, A. F., Coull, J. A., Chery, N., Poisbeau, P. & De Koninck, Y. Region-specific developmental specialization of GABA–glycine cosynapses in laminas I–II of the rat spinal dorsal horn. J. Neurosci. 21, 7871–7880 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Chen, Z. F. et al. The paired homeodomain protein DRG11 is required for the projection of cutaneous sensory afferent fibers to the dorsal spinal cord. Neuron 31, 59–73 (2001).

    Article  CAS  PubMed  Google Scholar 

  16. Dickson, B. J. Molecular mechanisms of axon guidance. Science 298, 1959–1964 (2002).

    Article  CAS  PubMed  Google Scholar 

  17. White, F. A. & Behar, O. The development and subsequent elimination of aberrant peripheral axon projections in Semaphorin3A null mutant mice. Dev. Biol. 225, 79–86 (2000).

    Article  CAS  PubMed  Google Scholar 

  18. Fitzgerald, M. Spontaneous and evoked activity of fetal primary afferents in vivo. Nature 326, 603–605 (1987).

    Article  CAS  PubMed  Google Scholar 

  19. Guo, A. et al. Developmental shift of vanilloid receptor 1 (VR1) terminals into deeper regions of the superficial dorsal horn: correlation with a shift from TrkA to Ret expression by dorsal root ganglion neurons. Eur. J. Neurosci. 14, 293–304 (2001).

    Article  CAS  PubMed  Google Scholar 

  20. Benn, S. C., Costigan, M., Tate, S., Fitzgerald, M. & Woolf, C. J. Developmental expression of the TTX-resistant voltage-gated sodium channels Nav1.8 (SNS) and Nav1.9 (SNS2) in primary sensory neurons. J. Neurosci. 21, 6077–6085 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Fitzgerald, M. The post-natal development of cutaneous afferent fibre input and receptive field organization in the rat dorsal horn. J. Physiol. (Lond.) 364, 1–18 (1985).

    Article  CAS  Google Scholar 

  22. Koltzenburg, M., Stucky, C. L. & Lewin, G. R. Receptive properties of mouse sensory neurons innervating hairy skin. J. Neurophysiol. 78, 1841–1850 (1997).

    Article  CAS  PubMed  Google Scholar 

  23. Koltzenburg, M. & Lewin, G. R. Receptive properties of embryonic chick sensory neurons innervating skin. J. Neurophysiol. 78, 2560–2568 (1997).

    Article  CAS  PubMed  Google Scholar 

  24. Constantinou, J., Reynolds, M. L., Woolf, C. J., Safieh-Garabedian, B. & Fitzgerald, M. Nerve growth factor levels in developing rat skin: upregulation following skin wounding. Neuroreport 5, 2281–2284 (1994).

    Article  CAS  PubMed  Google Scholar 

  25. Fitzgerald, M., Reynolds, M. L. & Benowitz, L. I. GAP-43 expression in the developing rat lumbar spinal cord. Neuroscience 41, 187–199 (1991).

    Article  CAS  PubMed  Google Scholar 

  26. Ozaki, S. & Snider, W. D. Initial trajectories of sensory axons toward laminar targets in the developing mouse spinal cord. J. Comp. Neurol. 380, 215–229 (1997).

    Article  CAS  PubMed  Google Scholar 

  27. Fitzgerald, M. & Swett, J. The termination pattern of sciatic nerve afferents in the substantia gelatinosa of neonatal rats. Neurosci. Lett. 43, 149–154 (1983).

    Article  CAS  PubMed  Google Scholar 

  28. Marti, E. et al. Ontogeny of peptide- and amine-containing neurones in motor, sensory, and autonomic regions of rat and human spinal cord, dorsal root ganglia, and rat skin. J. Comp. Neurol. 266, 332–359 (1987).

    Article  CAS  PubMed  Google Scholar 

  29. Pignatelli, D., Ribeiro-da-Silva, A. & Coimbra, A. Postnatal maturation of primary afferent terminations in the substantia gelatinosa of the rat spinal cord. An electron microscopic study. Brain Res. 491, 33–44 (1989).

    Article  CAS  PubMed  Google Scholar 

  30. Beggs, S., Torsney, C., Drew, L. J. & Fitzgerald, M. The postnatal reorganization of primary afferent input and dorsal horn cell receptive fields in the rat spinal cord is an activity-dependent process. Eur. J. Neurosci. 16, 1249–1258 (2002).

    Article  PubMed  Google Scholar 

  31. Torsney, C., Meredith-Middleton, J. & Fitzgerald, M. Neonatal capsaicin treatment prevents the normal postnatal withdrawal of A fibres from lamina II without affecting fos responses to innocuous peripheral stimulation. Brain Res. Dev. Brain Res. 121, 55–65 (2000).

    Article  CAS  PubMed  Google Scholar 

  32. Woodbury, C. J. & Koerber, H. R. Widespread projections from myelinated nociceptors throughout the substantia gelatinosa provide novel insights into neonatal hypersensitivity. J. Neurosci. 23, 601–610 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. Fitzgerald, M. Cutaneous primary afferent properties in the hind limb of the neonatal rat. J. Physiol. (Lond.) 383, 79–92 (1987).

    Article  CAS  Google Scholar 

  34. Woodbury, C. J., Ritter, A. M. & Koerber, H. R. Central anatomy of individual rapidly adapting low-threshold mechanoreceptors innervating the 'hairy' skin of newborn mice: early maturation of hair follicle afferents. J. Comp. Neurol. 436, 304–323 (2001).

    Article  CAS  PubMed  Google Scholar 

  35. Coggeshall, R. E., Jennings, E. A. & Fitzgerald, M. Evidence that large myelinated primary afferent fibers make synaptic contacts in lamina II of neonatal rats. Brain Res. Dev. Brain Res. 92, 81–90 (1996).

    Article  CAS  PubMed  Google Scholar 

  36. Ben Ari, Y. Excitatory actions of GABA during development: the nature of the nurture. Nature Rev. Neurosci. 3, 728–739 (2002).

    Article  CAS  Google Scholar 

  37. Nakatsuka, T., Ataka, T., Kumamoto, E., Tamaki, T. & Yoshimura, M. Alteration in synaptic inputs through C-afferent fibers to substantia gelatinosa neurons of the rat spinal dorsal horn during postnatal development. Neuroscience 99, 549–556 (2000).

    Article  CAS  PubMed  Google Scholar 

  38. Park, J. S., Nakatsuka, T., Nagata, K., Higashi, H. & Yoshimura, M. Reorganization of the primary afferent termination in the rat spinal dorsal horn during post-natal development. Brain Res. Dev. Brain Res. 113, 29–36 (1999).

    Article  CAS  PubMed  Google Scholar 

  39. Jennings, E. & Fitzgerald, M. C-fos can be induced in the neonatal rat spinal cord by both noxious and innocuous peripheral stimulation. Pain 68, 301–306 (1996).

    Article  CAS  PubMed  Google Scholar 

  40. Caspary, T. & Anderson, K. V. Patterning cell types in the dorsal spinal cord: what the mouse mutants say. Nature Rev. Neurosci. 4, 289–297 (2003).

    Article  CAS  Google Scholar 

  41. Gross, M. K., Dottori, M. & Goulding, M. Lbx1 specifies somatosensory association interneurons in the dorsal spinal cord. Neuron 34, 535–549 (2002).

    Article  CAS  PubMed  Google Scholar 

  42. Cheng, L. et al. Tlx3 and Tlx1 are post-mitotic selector genes determining glutamatergic over GABAergic cell fates. Nature Neurosci. 7, 510–517 (2004).

    Article  CAS  PubMed  Google Scholar 

  43. Bice, T. N. & Beal, J. A. Quantitative and neurogenic analysis of the total population and subpopulations of neurons defined by axon projection in the superficial dorsal horn of the rat lumbar spinal cord. J. Comp. Neurol. 388, 550–564 (1997).

    Article  CAS  PubMed  Google Scholar 

  44. Bice, T. N. & Beal, J. A. Quantitative and neurogenic analysis of neurons with supraspinal projections in the superficial dorsal horn of the rat lumbar spinal cord. J. Comp. Neurol. 388, 565–574 (1997).

    Article  CAS  PubMed  Google Scholar 

  45. Dahlhaus, A., Ruscheweyh, R. & Sandkuhler, J. Synaptic input of rat spinal lamina I projection and unidentified neurons in vitro. J. Physiol. (Lond.) 5 May 2005 (10.1113/jphysiol.2005.088567).

  46. Narayanan, C. H., Fox, M. W. & Hamburger, V. Prenatal development of spontaneous and evoked activity in the rat (Rattus norvegicus albinus). Behaviour 40, 100–134 (1971).

    Article  CAS  PubMed  Google Scholar 

  47. Saito, K. Development of spinal reflexes in the rat fetus studied in vitro. J. Physiol. (Lond.) 294, 581–594 (1979).

    Article  CAS  Google Scholar 

  48. Andrews, K. & Fitzgerald, M. The cutaneous withdrawal reflex in human neonates: sensitization, receptive fields, and the effects of contralateral stimulation. Pain 56, 95–101 (1994).

    Article  CAS  PubMed  Google Scholar 

  49. Andrews, K. & Fitzgerald, M. Cutaneous flexion reflex in human neonates: a quantitative study of threshold and stimulus-response characteristics after single and repeated stimuli. Dev. Med. Child Neurol. 41, 696–703 (1999).

    Article  CAS  PubMed  Google Scholar 

  50. Andrews, K. A., Desai, D., Dhillon, H. K., Wilcox, D. T. & Fitzgerald, M. Abdominal sensitivity in the first year of life: comparison of infants with and without prenatally diagnosed unilateral hydronephrosis. Pain 100, 35–46 (2002).

    Article  CAS  PubMed  Google Scholar 

  51. Ekholm, J. Postnatal changes in cutaneous reflexes and in the discharge pattern of cutaneous and articular sense organs. A morphological and physiological study in the cat. Acta Physiol. Scand. 297 (Suppl.), 1–130 (1967).

    CAS  Google Scholar 

  52. Fitzgerald, M., Shaw, A. & MacIntosh, N. Postnatal development of the cutaneous flexor reflex: comparative study of preterm infants and newborn rat pups. Dev. Med. Child Neurol. 30, 520–526 (1988).

    Article  CAS  PubMed  Google Scholar 

  53. Falcon, M., Guendellman, D., Stolberg, A., Frenk, H. & Urca, G. Development of thermal nociception in rats. Pain 67, 203–208 (1996).

    Article  CAS  PubMed  Google Scholar 

  54. Teng, C. J. & Abbott, F. V. The formalin test: a dose-response analysis at three developmental stages. Pain 76, 337–347 (1998).

    Article  CAS  PubMed  Google Scholar 

  55. Waldenstrom, A., Thelin, J., Thimansson, E., Levinsson, A. & Schouenborg, J. Developmental learning in a pain-related system: evidence for a cross-modality mechanism. J. Neurosci. 23, 7719–7725 (2003).

    Article  PubMed  PubMed Central  Google Scholar 

  56. Schouenborg, J. Somatosensory imprinting in spinal reflex modules. J. Rehabil. Med. 73–80 (2003).

  57. Baccei, M. L., Bardoni, R. & Fitzgerald, M. Development of nociceptive synaptic inputs to the neonatal rat dorsal horn: glutamate release by capsaicin and menthol. J. Physiol. (Lond.) 549, 231–242 (2003).

    Article  CAS  Google Scholar 

  58. Fitzgerald, M. & Jennings, E. The postnatal development of spinal sensory processing. Proc. Natl Acad. Sci. USA 96, 7719–7722 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Torsney, C. & Fitzgerald, M. Age-dependent effects of peripheral inflammation on the electrophysiological properties of neonatal rat dorsal horn neurons. J. Neurophysiol. 87, 1311–1317 (2002).

    Article  PubMed  Google Scholar 

  60. Jennings, E. & Fitzgerald, M. Postnatal changes in responses of rat dorsal horn cells to afferent stimulation: a fibre-induced sensitization. J. Physiol. (Lond.) 509, 859–868 (1998).

    Article  CAS  Google Scholar 

  61. Fitzgerald, M., King, A. E., Thompson, S. W. & Woolf, C. J. The postnatal development of the ventral root reflex in the rat; a comparative in vivo and in vitro study. Neurosci. Lett. 78, 41–45 (1987).

    Article  CAS  PubMed  Google Scholar 

  62. Fitzgerald, M. The development of activity evoked by fine diameter cutaneous fibres in the spinal cord of the newborn rat. Neurosci. Lett. 86, 161–166 (1988).

    Article  CAS  PubMed  Google Scholar 

  63. Hori, Y. & Watanabe, S. Morphine-sensitive late components of the flexion reflex in the neonatal rat. Neurosci. Lett. 78, 91–96 (1987).

    Article  CAS  PubMed  Google Scholar 

  64. Fitzgerald, M. & Gibson, S. The postnatal physiological and neurochemical development of peripheral sensory C fibres. Neuroscience 13, 933–944 (1984).

    Article  CAS  PubMed  Google Scholar 

  65. Soyguder, Z., Schmidt, H. H. & Morris, R. Postnatal development of nitric oxide synthase type 1 expression in the lumbar spinal cord of the rat: a comparison with the induction of c-fos in response to peripheral application of mustard oil. Neurosci. Lett. 180, 188–192 (1994).

    Article  CAS  PubMed  Google Scholar 

  66. Baba, H., Doubell, T. P., Moore, K. A. & Woolf, C. J. Silent NMDA receptor-mediated synapses are developmentally regulated in the dorsal horn of the rat spinal cord. J. Neurophysiol. 83, 955–962 (2000).

    Article  CAS  PubMed  Google Scholar 

  67. Bardoni, R., Magherini, P. C. & MacDermott, A. B. Activation of NMDA receptors drives action potentials in superficial dorsal horn from neonatal rats. Neuroreport 11, 1721–1727 (2000).

    Article  CAS  PubMed  Google Scholar 

  68. Li, P. & Zhuo, M. Silent glutamatergic synapses and nociception in mammalian spinal cord. Nature 393, 695–698 (1998).

    Article  CAS  PubMed  Google Scholar 

  69. Liu, G. Local structural balance and functional interaction of excitatory and inhibitory synapses in hippocampal dendrites. Nature Neurosci. 7, 373–379 (2004).

    Article  CAS  PubMed  Google Scholar 

  70. Baccei, M. L. & Fitzgerald, M. Development of GABAergic and glycinergic transmission in the neonatal rat dorsal horn. J. Neurosci. 24, 4749–4757 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  71. Keller, A. F., Breton, J. D., Schlichter, R. & Poisbeau, P. Production of 5α-reduced neurosteroids is developmentally regulated and shapes GABAA miniature IPSCs in lamina II of the spinal cord. J. Neurosci. 24, 907–915 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  72. Tao, H. W. & Poo, M. M. Activity-dependent matching of excitatory and inhibitory inputs during refinement of visual receptive fields. Neuron 45, 829–836 (2005).

    Article  CAS  PubMed  Google Scholar 

  73. Chen, J. H., Weng, H. R. & Dougherty, P. M. Sensitization of dorsal root reflexes in vitro and hyperalgesia in neonatal rats produced by capsaicin. Neuroscience 126, 743–751 (2004).

    Article  CAS  PubMed  Google Scholar 

  74. Weber, E. D. & Stelzner, D. J. Behavioral effects of spinal cord transection in the developing rat. Brain Res. 125, 241–255 (1977).

    Article  CAS  PubMed  Google Scholar 

  75. Rajaofetra, N., Sandillon, F., Geffard, M. & Privat, A. Pre- and post-natal ontogeny of serotonergic projections to the rat spinal cord. J. Neurosci. Res. 22, 305–321 (1989).

    Article  CAS  PubMed  Google Scholar 

  76. Bregman, B. S. Development of serotonin immunoreactivity in the rat spinal cord and its plasticity after neonatal spinal cord lesions. Brain Res. 431, 245–263 (1987).

    Article  CAS  PubMed  Google Scholar 

  77. van Praag, H. & Frenk, H. The development of stimulation-produced analgesia (SPA) in the rat. Brain Res. Dev. Brain Res. 64, 71–76 (1991).

    Article  CAS  PubMed  Google Scholar 

  78. Boucher, T., Jennings, E. & Fitzgerald, M. The onset of diffuse noxious inhibitory controls in postnatal rat pups: a C-Fos study. Neurosci. Lett. 257, 9–12 (1998).

    Article  CAS  PubMed  Google Scholar 

  79. Fitzgerald, M. & Koltzenburg, M. The functional development of descending inhibitory pathways in the dorsolateral funiculus of the newborn rat spinal cord. Brain Res. 389, 261–270 (1986).

    Article  CAS  PubMed  Google Scholar 

  80. Guy, E. R. & Abbott, F. V. The behavioral response to formalin in preweanling rats. Pain 51, 81–90 (1992).

    Article  CAS  PubMed  Google Scholar 

  81. Abbott, F. V. & Guy, E. R. Effects of morphine, pentobarbital and amphetamine on formalin-induced behaviours in infant rats: sedation versus specific suppression of pain. Pain 62, 303–312 (1995).

    Article  CAS  PubMed  Google Scholar 

  82. Giordano, J. Antinociceptive effects of intrathecally administered 2-methylserotonin in developing rats. Brain Res. Dev. Brain Res. 98, 142–144 (1997).

    Article  CAS  PubMed  Google Scholar 

  83. Millan, M. J. Descending control of pain. Prog. Neurobiol. 66, 355–474 (2002).

    Article  CAS  PubMed  Google Scholar 

  84. Kendig, J. J., Savola, M. K., Woodley, S. J. & Maze, M. α2-adrenoceptors inhibit a nociceptive response in neonatal rat spinal cord. Eur. J. Pharmacol. 192, 293–300 (1991).

    Article  CAS  PubMed  Google Scholar 

  85. Hughes, H. E. & Barr, G. A. Analgesic effects of intrathecally applied noradrenergic compounds in the developing rat: differences due to thermal vs mechanical nociception. Brain Res. 469, 109–120 (1988).

    Article  CAS  PubMed  Google Scholar 

  86. Walker, S. M., Howard, R. H., Keay, K. A. & Fitzgerald, M. Developmental age influences the effect of epidural dexmedetomidine on inflammatory hyperalgesia in the rat pup. Anesthesiology 102, 1226–1234 (2005).

    Article  CAS  PubMed  Google Scholar 

  87. Hori, Y. & Kanda, K. Developmental alterations in NMDA receptor-mediated [Ca2+]i elevation in substantia gelatinosa neurons of neonatal rat spinal cord. Brain Res. Dev. Brain Res. 80, 141–148 (1994).

    Article  CAS  PubMed  Google Scholar 

  88. Shortland, P., Molander, C., Woolf, C. J. & Fitzgerald, M. Neonatal capsaicin treatment induces invasion of the substantia gelatinosa by the terminal arborizations of hair follicle afferents in the rat dorsal horn. J. Comp. Neurol. 296, 23–31 (1990).

    Article  CAS  PubMed  Google Scholar 

  89. Yang, K., Furue, H., Fujita, T., Kumamoto, E. & Yoshimura, M. Alterations in primary afferent input to substantia gelatinosa of adult rat spinal cord after neonatal capsaicin treatment. J. Neurosci. Res. 74, 928–933 (2003).

    Article  CAS  PubMed  Google Scholar 

  90. Ohtori, S. et al. Neonatal capsaicin treatment decreased substance P receptor immunoreactivity in lamina III neurons of the dorsal horn. Neurosci. Res. 38, 147–154 (2000).

    Article  CAS  PubMed  Google Scholar 

  91. Cervero, F. & Plenderleith, M. B. C-fibre excitation and tonic descending inhibition of dorsal horn neurones in adult rats treated at birth with capsaicin. J. Physiol. (Lond.) 365, 223–237 (1985).

    Article  CAS  Google Scholar 

  92. Chiang, C. Y., Hu, J. W. & Sessle, B. J. NMDA receptor involvement in neuroplastic changes induced by neonatal capsaicin treatment in trigeminal nociceptive neurons. J. Neurophysiol. 78, 2799–2803 (1997).

    Article  CAS  PubMed  Google Scholar 

  93. Wall, P. D., Fitzgerald, M., Nussbaumer, J. C., Van der Loos, H. & Devor, M. Somatotopic maps are disorganized in adult rodents treated neonatally with capsaicin. Nature 295, 691–693 (1982).

    Article  CAS  PubMed  Google Scholar 

  94. Sutton, M. A., Wall, N. R., Aakalu, G. N. & Schuman, E. M. Regulation of dendritic protein synthesis by miniature synaptic events. Science 304, 1979–1983 (2004).

    Article  CAS  PubMed  Google Scholar 

  95. Petersson, P., Waldenstrom, A., Fahraeus, C. & Schouenborg, J. Spontaneous muscle twitches during sleep guide spinal self-organization. Nature 424, 72–75 (2003).

    Article  CAS  PubMed  Google Scholar 

  96. Petersson, P., Granmo, M. & Schouenborg, J. Properties of an adult spinal sensorimotor circuit shaped through early postnatal experience. J. Neurophysiol. 92, 280–288 (2004).

    Article  CAS  PubMed  Google Scholar 

  97. Sandkuhler, J., Chen, J. G., Cheng, G. & Randic, M. Low-frequency stimulation of afferent Aδ-fibers induces long-term depression at primary afferent synapses with substantia gelatinosa neurons in the rat. J. Neurosci. 17, 6483–6491 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  98. Sivilotti, L. G., Thompson, S. W. & Woolf, C. J. Rate of rise of the cumulative depolarization evoked by repetitive stimulation of small-caliber afferents is a predictor of action potential windup in rat spinal neurons in vitro. J. Neurophysiol. 69, 1621–1631 (1993).

    Article  CAS  PubMed  Google Scholar 

  99. Thompson, S. W., Gerber, G., Sivilotti, L. G. & Woolf, C. J. Long duration ventral root potentials in the neonatal rat spinal cord in vitro; the effects of ionotropic and metabotropic excitatory amino acid receptor antagonists. Brain Res. 595, 87–97 (1992).

    Article  CAS  PubMed  Google Scholar 

  100. Azkue, J. J., Liu, X. G., Zimmermann, M. & Sandkuhler, J. Induction of long-term potentiation of C fibre-evoked spinal field potentials requires recruitment of group I, but not group II/III metabotropic glutamate receptors. Pain 106, 373–379 (2003).

    Article  CAS  PubMed  Google Scholar 

  101. Howard, R. F., Hatch, D. J., Cole, T. J. & Fitzgerald, M. Inflammatory pain and hypersensitivity are selectively reversed by epidural bupivacaine and are developmentally regulated. Anesthesiology 95, 421–427 (2001).

    Article  CAS  PubMed  Google Scholar 

  102. Jiang, M. C. & Gebhart, G. F. Development of mustard oil-induced hyperalgesia in rats. Pain 77, 305–313 (1998).

    Article  CAS  PubMed  Google Scholar 

  103. Marsh, D., Dickenson, A., Hatch, D. & Fitzgerald, M. Epidural opioid analgesia in infant rats II: responses to carrageenan and capsaicin. Pain 82, 33–38 (1999).

    Article  CAS  PubMed  Google Scholar 

  104. Yi, D. K. & Barr, G. A. The induction of Fos-like immunoreactivity by noxious thermal, mechanical and chemical stimuli in the lumbar spinal cord of infant rats. Pain 60, 257–265 (1995).

    Article  CAS  PubMed  Google Scholar 

  105. Holsti, L., Grunau, R. E., Oberlander, T. F. & Whitfield, M. F. Prior pain induces heightened motor responses during clustered care in preterm infants in the NICU. Early Hum. Dev. 81, 293–302 (2005).

    Article  PubMed  Google Scholar 

  106. Ikeda, H., Heinke, B., Ruscheweyh, R. & Sandkuhler, J. Synaptic plasticity in spinal lamina I projection neurons that mediate hyperalgesia. Science 299, 1237–1240 (2003).

    Article  CAS  PubMed  Google Scholar 

  107. Miletic, V. & Randic, M. Neonatal rat spinal cord slice preparation: postsynaptic effects of neuropeptides on dorsal horn neurons. Brain Res. 254, 432–438 (1981).

    Article  CAS  PubMed  Google Scholar 

  108. Kar, S. & Quirion, R. Neuropeptide receptors in developing and adult rat spinal cord: an in vitro quantitative autoradiography study of calcitonin gene-related peptide, neurokinins, μ-opioid, galanin, somatostatin, neurotensin and vasoactive intestinal polypeptide receptors. J. Comp. Neurol. 354, 253–281 (1995).

    Article  CAS  PubMed  Google Scholar 

  109. Beland, B. & Fitzgerald, M. Influence of peripheral inflammation on the postnatal maturation of primary sensory neuron phenotype in rats. J. Pain 2, 36–45 (2001).

    Article  CAS  PubMed  Google Scholar 

  110. Zhu, W., Galoyan, S. M., Petruska, J. C., Oxford, G. S. & Mendell, L. M. A developmental switch in acute sensitization of small dorsal root ganglion (DRG) neurons to capsaicin or noxious heating by NGF. J. Neurophysiol. 92, 3148–3152 (2004).

    Article  CAS  PubMed  Google Scholar 

  111. Bonnington, J. K. & McNaughton, P. A. Signalling pathways involved in the sensitisation of mouse nociceptive neurones by nerve growth factor. J. Physiol. (Lond.) 551, 433–446 (2003).

    Article  CAS  Google Scholar 

  112. Ling, Q. D., Chien, C. C., Wen, Y. R., Fu, W. M. & Sun, W. Z. The pattern and distribution of calcitonin gene-related peptide (CGRP) terminals in the rat dorsal following neonatal peripheral inflammation. Neuroreport 14, 1919–1921 (2003).

    Article  CAS  PubMed  Google Scholar 

  113. Walker, S. M., Meredith-Middleton, J., Cooke-Yarborough, C. & Fitzgerald, M. Neonatal inflammation and primary afferent terminal plasticity in the rat dorsal horn. Pain 105, 185–195 (2003).

    Article  PubMed  Google Scholar 

  114. Sweitzer, S. M. et al. Protein kinase C ε and γ: involvement in formalin-induced nociception in neonatal rats. J. Pharmacol. Exp. Ther. 309, 616–625 (2004).

    Article  CAS  PubMed  Google Scholar 

  115. Grunau, R. Early pain in preterm infants. A model of long-term effects. Clin. Perinatol. 29, 373–394; vii–viii (2002).

    Article  PubMed  Google Scholar 

  116. Anand, K. J. Pain, plasticity, and premature birth: a prescription for permanent suffering? Nature Med. 6, 971–973 (2000).

    Article  CAS  PubMed  Google Scholar 

  117. Peters, J. W. et al. Does neonatal surgery lead to increased pain sensitivity in later childhood? Pain 114, 444–454 (2005).

    Article  PubMed  Google Scholar 

  118. Anand, K. J., Coskun, V., Thrivikraman, K. V., Nemeroff, C. B. & Plotsky, P. M. Long-term behavioral effects of repetitive pain in neonatal rat pups. Physiol. Behav. 66, 627–637 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  119. Johnston, C. C. & Walker, C. D. The effects of exposure to repeated minor pain during the neonatal period on formalin pain behaviour and thermal withdrawal latencies. Pain Res. Manag. 8, 213–217 (2003).

    Article  PubMed  Google Scholar 

  120. Ren, K. et al. Characterization of basal and re-inflammation-associated long-term alteration in pain responsivity following short-lasting neonatal local inflammatory insult. Pain 110, 588–596 (2004).

    Article  CAS  PubMed  Google Scholar 

  121. Ruda, M. A., Ling, Q. D., Hohmann, A. G., Peng, Y. B. & Tachibana, T. Altered nociceptive neuronal circuits after neonatal peripheral inflammation. Science 289, 628–631 (2000).

    Article  CAS  PubMed  Google Scholar 

  122. Tachibana, T., Ling, Q. D. & Ruda, M. A. Increased Fos induction in adult rats that experienced neonatal peripheral inflammation. Neuroreport 12, 925–927 (2001).

    Article  CAS  PubMed  Google Scholar 

  123. Alvares, D., Torsney, C., Beland, B., Reynolds, M. & Fitzgerald, M. Modelling the prolonged effects of neonatal pain. Prog. Brain Res. 129, 365–373 (2000).

    Article  CAS  PubMed  Google Scholar 

  124. Al Chaer, E. D., Kawasaki, M. & Pasricha, P. J. A new model of chronic visceral hypersensitivity in adult rats induced by colon irritation during postnatal development. Gastroenterology 119, 1276–1285 (2000).

    Article  CAS  PubMed  Google Scholar 

  125. Reynolds, M. L. & Fitzgerald, M. Long-term sensory hyperinnervation following neonatal skin wounds. J. Comp. Neurol. 358, 487–498 (1995).

    Article  CAS  PubMed  Google Scholar 

  126. Torsney, C. & Fitzgerald, M. Spinal dorsal horn cell receptive field size is increased in adult rats following neonatal hindpaw skin injury. J. Physiol. (Lond.) 550, 255–261 (2003).

    Article  CAS  Google Scholar 

  127. Shimada, C., Kurumiya, S., Noguchi, Y. & Umemoto, M. The effect of neonatal exposure to chronic footshock on pain-responsiveness and sensitivity to morphine after maturation in the rat. Behav. Brain Res. 36, 105–111 (1990).

    Article  CAS  PubMed  Google Scholar 

  128. Bhutta, A. T. et al. Interactions of inflammatory pain and morphine in infant rats: long-term behavioral effects. Physiol. Behav. 73, 51–58 (2001).

    Article  CAS  PubMed  Google Scholar 

  129. De Lima, J., Alvares, D., Hatch, D. J. & Fitzgerald, M. Sensory hyperinnervation after neonatal skin wounding: effect of bupivacaine sciatic nerve block. Br. J. Anaesth. 83, 662–664 (1999).

    Article  CAS  PubMed  Google Scholar 

  130. d'Amore, A., Mazzucchelli, A. & Loizzo, A. Long-term changes induced by neonatal handling in the nociceptive threshold and body weight in mice. Physiol. Behav. 57, 1195–1197 (1995).

    Article  CAS  PubMed  Google Scholar 

  131. Sternberg, W. F. & Ridgway, C. G. Effects of gestational stress and neonatal handling on pain, analgesia, and stress behavior of adult mice. Physiol. Behav. 78, 375–383 (2003).

    Article  CAS  PubMed  Google Scholar 

  132. Howard, R. F., Walker, S. M., Michael Mota, P. & Fitzgerald, M. The ontogeny of neuropathic pain: postnatal onset of mechanical allodynia in rat spared nerve injury (SNI) and chronic constriction injury (CCI) models. Pain 115, 382–389 (2005).

    Article  PubMed  Google Scholar 

  133. Lee, D. H. & Chung, J. M. Neuropathic pain in neonatal rats. Neurosci. Lett. 209, 140–142 (1996).

    Article  CAS  PubMed  Google Scholar 

  134. Anand, P. & Birch, R. Restoration of sensory function and lack of long-term chronic pain syndromes after brachial plexus injury in human neonates. Brain 125, 113–122 (2002).

    Article  CAS  PubMed  Google Scholar 

  135. Schmalbruch, H. Loss of sensory neurons after sciatic nerve section in the rat. Anat. Rec. 219, 323–329 (1987).

    Article  CAS  PubMed  Google Scholar 

  136. Himes, B. T. & Tessler, A. Death of some dorsal root ganglion neurons and plasticity of others following sciatic nerve section in adult and neonatal rats. J. Comp. Neurol. 284, 215–230 (1989).

    Article  CAS  PubMed  Google Scholar 

  137. Oliveira, A. L. et al. Neonatal sciatic nerve transection induces TUNEL labeling of neurons in the rat spinal cord and DRG. Neuroreport 8, 2837–2840 (1997).

    Article  CAS  PubMed  Google Scholar 

  138. Whiteside, G., Doyle, C. A., Hunt, S. P. & Munglani, R. Differential time course of neuronal and glial apoptosis in neonatal rat dorsal root ganglia after sciatic nerve axotomy. Eur. J. Neurosci. 10, 3400–3408 (1998).

    Article  CAS  PubMed  Google Scholar 

  139. Fitzgerald, M., Woolf, C. J. & Shortland, P. Collateral sprouting of the central terminals of cutaneous primary afferent neurons in the rat spinal cord: pattern, morphology, and influence of targets. J. Comp. Neurol. 300, 370–385 (1990).

    Article  CAS  PubMed  Google Scholar 

  140. Shortland, P. & Fitzgerald, M. Functional connections formed by saphenous nerve terminal sprouts in the dorsal horn following neonatal sciatic nerve section. Eur. J. Neurosci. 3, 383–396 (1991).

    Article  PubMed  Google Scholar 

  141. Reynolds, M. L. & Fitzgerald, M. Neonatal sciatic nerve section results in thiamine monophosphate but not substance P or calcitonin gene-related peptide depletion from the terminal field in the dorsal horn of the rat: the role of collateral sprouting. Neuroscience 51, 191–202 (1992).

    Article  CAS  PubMed  Google Scholar 

  142. Woolf, C. J. & Salter, M. W. Neuronal plasticity: increasing the gain in pain. Science 288, 1765–1769 (2000).

    Article  CAS  PubMed  Google Scholar 

  143. Tsuda, M., Inoue, K. & Salter, M. W. Neuropathic pain and spinal microglia: a big problem from molecules in 'small' glia. Trends Neurosci. 28, 101–107 (2005).

    Article  CAS  PubMed  Google Scholar 

  144. Mellor, D. J., Diesch, T. J., Gunn, A. J. & Bennet, L. The importance of 'awareness' for understanding fetal pain. Brain Res. Rev 13 Mar 2005 (10.1016/j.brainresrev.2005.01.006).

  145. Oberlander, T. F., Grunau, R. E., Fitzgerald, C. & Whitfield, M. F. Does parenchymal brain injury affect biobehavioral pain responses in very low birth weight infants at 32 weeks' postconceptional age? Pediatrics 110, 570–576 (2002).

    Article  PubMed  Google Scholar 

  146. Berde, C. B. & Sethna, N. F. Analgesics for the treatment of pain in children. N. Engl. J. Med. 347, 1094–1103 (2002).

    Article  CAS  PubMed  Google Scholar 

  147. Howard, R. F. Current status of pain management in children. JAMA 290, 2464–2469 (2003).

    Article  CAS  PubMed  Google Scholar 

  148. Bouwmeester, N. J. et al. Postoperative pain in the neonate: age-related differences in morphine requirements and metabolism. Intensive Care Med. 29, 2009–2015 (2003).

    Article  PubMed  Google Scholar 

  149. Marsh, D., Dickenson, A., Hatch, D. & Fitzgerald, M. Epidural opioid analgesia in infant rats I: mechanical and heat responses. Pain 82, 23–32 (1999).

    Article  CAS  PubMed  Google Scholar 

  150. Nandi, R. et al. The functional expression of μ opioid receptors on sensory neurons is developmentally regulated; morphine analgesia is less selective in the neonate. Pain 111, 38–50 (2004).

    Article  CAS  PubMed  Google Scholar 

  151. Attali, B., Saya, D. & Vogel, Z. Pre- and postnatal development of opiate receptor subtypes in rat spinal cord. Brain Res. Dev. Brain Res. 53, 97–102 (1990).

    Article  CAS  PubMed  Google Scholar 

  152. Rahman, W., Dashwood, M. R., Fitzgerald, M., Aynsley-Green, A. & Dickenson, A. H. Postnatal development of multiple opioid receptors in the spinal cord and development of spinal morphine analgesia. Brain Res. Dev. Brain Res. 108, 239–254 (1998).

    Article  CAS  PubMed  Google Scholar 

  153. Williams, D. G., Dickenson, A., Fitzgerald, M. & Howard, R. F. Developmental regulation of codeine analgesia in the rat. Anesthesiology 100, 92–97 (2004).

    Article  CAS  PubMed  Google Scholar 

  154. Ririe, D. G., Prout, H. M. & Eisenach, J. C. Effect of cyclooxygenase-1 inhibition in postoperative pain is developmentally regulated. Anesthesiology 101, 1031–1035 (2004).

    Article  PubMed  Google Scholar 

  155. Jakowec, M. W., Fox, A. J., Martin, L. J. & Kalb, R. G. Quantitative and qualitative changes in AMPA receptor expression during spinal cord development. Neuroscience 67, 893–907 (1995).

    Article  CAS  PubMed  Google Scholar 

  156. Burnashev, N. et al. Calcium-permeable AMPA-kainate receptors in fusiform cerebellar glial cells. Science 256, 1566–1570 (1992).

    Article  CAS  PubMed  Google Scholar 

  157. Albuquerque, C., Lee, C. J., Jackson, A. C. & MacDermott, A. B. Subpopulations of GABAergic and non-GABAergic rat dorsal horn neurons express Ca2+-permeable AMPA receptors. Eur. J. Neurosci. 11, 2758–2766 (1999).

    Article  CAS  PubMed  Google Scholar 

  158. Engelman, H. S., Allen, T. B. & MacDermott, A. B. The distribution of neurons expressing calcium-permeable AMPA receptors in the superficial laminae of the spinal cord dorsal horn. J. Neurosci. 19, 2081–2089 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  159. Li, P. et al. Kainate-receptor-mediated sensory synaptic transmission in mammalian spinal cord. Nature 397, 161–164 (1999).

    Article  CAS  PubMed  Google Scholar 

  160. Stegenga, S. L. & Kalb, R. G. Developmental regulation of N-methyl-D-aspartate- and kainate-type glutamate receptor expression in the rat spinal cord. Neuroscience 105, 499–507 (2001).

    Article  CAS  PubMed  Google Scholar 

  161. Agrawal, S. G. & Evans, R. H. The primary afferent depolarizing action of kainate in the rat. Br. J. Pharmacol. 87, 345–355 (1986).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  162. Kerchner, G. A., Wilding, T. J., Li, P., Zhuo, M. & Huettner, J. E. Presynaptic kainate receptors regulate spinal sensory transmission. J. Neurosci. 21, 59–66 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  163. Lee, C. J. et al. Kainate receptors expressed by a subpopulation of developing nociceptors rapidly switch from high to low Ca2+ permeability. J. Neurosci. 21, 4572–4581 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  164. Gonzalez, D. L., Fuchs, J. L. & Droge, M. H. Distribution of NMDA receptor binding in developing mouse spinal cord. Neurosci. Lett. 151, 134–137 (1993).

    Article  CAS  PubMed  Google Scholar 

  165. Watanabe, M., Mishina, M. & Inoue, Y. Distinct spatiotemporal distributions of the N-methyl-D-aspartate receptor channel subunit mRNAs in the mouse cervical cord. J. Comp. Neurol. 345, 314–319 (1994).

    Article  CAS  PubMed  Google Scholar 

  166. Bardoni, R. Excitatory synaptic transmission in neonatal dorsal horn: NMDA and ATP receptors. News Physiol. Sci. 16, 95–100 (2001).

    CAS  PubMed  Google Scholar 

  167. Monyer, H., Burnashev, N., Laurie, D. J., Sakmann, B. & Seeburg, P. H. Developmental and regional expression in the rat brain and functional properties of four NMDA receptors. Neuron 12, 529–540 (1994).

    Article  CAS  PubMed  Google Scholar 

  168. Wang, J., Reichling, D. B., Kyrozis, A. & MacDermott, A. B. Developmental loss of GABA- and glycine-induced depolarization and Ca2+ transients in embryonic rat dorsal horn neurons in culture. Eur. J. Neurosci. 6, 1275–1280 (1994).

    Article  CAS  PubMed  Google Scholar 

  169. Green, G. M. & Gibb, A. J. Characterization of the single-channel properties of NMDA receptors in laminae I and II of the dorsal horn of neonatal rat spinal cord. Eur. J. Neurosci. 14, 1590–1602 (2001).

    Article  CAS  PubMed  Google Scholar 

  170. Berthele, A. et al. Distribution and developmental changes in metabotropic glutamate receptor messenger RNA expression in the rat lumbar spinal cord. Brain Res. Dev. Brain Res. 112, 39–53 (1999).

    Article  CAS  PubMed  Google Scholar 

  171. Valerio, A. et al. mGluR5 metabotropic glutamate receptor distribution in rat and human spinal cord: a developmental study. Neurosci. Res. 28, 49–57 (1997).

    Article  CAS  PubMed  Google Scholar 

  172. Somogyi, R., Wen, X., Ma, W. & Barker, J. L. Developmental kinetics of GAD family mRNAs parallel neurogenesis in the rat spinal cord. J. Neurosci. 15, 2575–2591 (1995).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  173. Ma, W., Behar, T. & Barker, J. L. Transient expression of GABA immunoreactivity in the developing rat spinal cord. J. Comp. Neurol. 325, 271–290 (1992).

    Article  CAS  PubMed  Google Scholar 

  174. Schaffner, A. E., Behar, T., Nadi, S., Smallwood, V. & Barker, J. L. Quantitative analysis of transient GABA expression in embryonic and early postnatal rat spinal cord neurons. Brain Res. Dev. Brain Res. 72, 265–276 (1993).

    Article  CAS  PubMed  Google Scholar 

  175. Poyatos, I., Ponce, J., Aragon, C., Gimenez, C. & Zafra, F. The glycine transporter GLYT2 is a reliable marker for glycine-immunoreactive neurons. Brain Res. Mol. Brain Res. 49, 63–70 (1997).

    Article  CAS  PubMed  Google Scholar 

  176. Reichling, D. B., Kyrozis, A., Wang, J. & MacDermott, A. B. Mechanisms of GABA and glycine depolarization-induced calcium transients in rat dorsal horn neurons. J. Physiol. (Lond.) 476, 411–421 (1994).

    Article  CAS  Google Scholar 

  177. Serafini, R., Valeyev, A. Y., Barker, J. L. & Poulter, M. O. Depolarizing GABA-activated Cl channels in embryonic rat spinal and olfactory bulb cells. J. Physiol. (Lond.) 488, 371–386 (1995).

    Article  CAS  Google Scholar 

  178. Khazipov, R., Leinekugel, X., Khalilov, I., Gaiarsa, J. L. & Ben Ari, Y. Synchronization of GABAergic interneuronal network in CA3 subfield of neonatal rat hippocampal slices. J. Physiol. (Lond.) 498, 763–772 (1997).

    Article  CAS  Google Scholar 

  179. Sands, S. A., Purisai, M. G., Chronwall, B. M. & Enna, S. J. Ontogeny of GABAB receptor subunit expression and function in the rat spinal cord. Brain Res. 972, 197–206 (2003).

    Article  CAS  PubMed  Google Scholar 

  180. Rozzo, A. et al. Expression and dendritic mRNA localization of GABAC receptor rho1 and rho2 subunits in developing rat brain and spinal cord. Eur. J. Neurosci. 15, 1747–1758 (2002).

    Article  PubMed  Google Scholar 

  181. Blake, J. F. et al. Antagonism of baclofen-induced depression of whole-cell synaptic currents in spinal dorsal horn neurones by the potent GABAB antagonist CGP55845. Neuropharmacology 32, 1437–1440 (1993).

    Article  CAS  PubMed  Google Scholar 

  182. Moqrich, A. et al. Expressing TrkC from the TrkA locus causes a subset of dorsal root ganglia neurons to switch fate. Nature Neurosci. 7, 812–818 (2004).

    Article  CAS  PubMed  Google Scholar 

  183. Snider, W. D. & Silos-Santiago, I. Dorsal root ganglion neurons require functional neurotrophin receptors for survival during development. Philos. Trans. R. Soc. Lond. B 351, 395–403 (1996).

    Article  CAS  Google Scholar 

  184. Guha, U. et al. Target-derived BMP signaling limits sensory neuron number and the extent of peripheral innervation in vivo. Development 131, 1175–1186 (2004).

    Article  CAS  PubMed  Google Scholar 

  185. Lewis, S. E. et al. A role for HSP27 in sensory neuron survival. J. Neurosci. 19, 8945–8953 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  186. Patel, T. D., Jackman, A., Rice, F. L., Kucera, J. & Snider, W. D. Development of sensory neurons in the absence of NGF/TrkA signaling in vivo. Neuron 25, 345–357 (2000).

    Article  CAS  PubMed  Google Scholar 

  187. Bennett, D. L., Averill, S., Clary, D. O., Priestley, J. V. & McMahon, S. B. Postnatal changes in the expression of the trkA high-affinity NGF receptor in primary sensory neurons. Eur. J. Neurosci. 8, 2204–2208 (1996).

    Article  CAS  PubMed  Google Scholar 

  188. Molliver, D. C. et al. IB4-binding DRG neurons switch from NGF to GDNF dependence in early postnatal life. Neuron 19, 849–861 (1997).

    Article  CAS  PubMed  Google Scholar 

  189. Davies, A. M. Neurotrophins: more to NGF than just survival. Curr. Biol. 10, R374–R376 (2000).

    Article  CAS  PubMed  Google Scholar 

  190. Markus, A., Zhong, J. & Snider, W. D. Raf and Akt mediate distinct aspects of sensory axon growth. Neuron 35, 65–76 (2002).

    Article  CAS  PubMed  Google Scholar 

  191. Lewin, G. R. & Mendell, L. M. Regulation of cutaneous C-fiber heat nociceptors by nerve growth factor in the developing rat. J. Neurophysiol. 71, 941–949 (1994).

    Article  CAS  PubMed  Google Scholar 

  192. Lewin, G. R. Neurotrophins and the specification of neuronal phenotype. Philos. Trans. R. Soc. Lond. B 351, 405–411 (1996).

    Article  CAS  Google Scholar 

  193. Ritter, A. M., Lewin, G. R., Kremer, N. E. & Mendell, L. M. Requirement for nerve growth factor in the development of myelinated nociceptors in vivo. Nature 350, 500–502 (1991).

    Article  CAS  PubMed  Google Scholar 

  194. Hall, A. K. et al. The generation of neuronal heterogeneity in a rat sensory ganglion. J. Neurosci. 17, 2775–2784 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  195. Hall, A. K., Dinsio, K. J. & Cappuzzello, J. Skin cell induction of calcitonin gene-related peptide in embryonic sensory neurons in vitro involves activin. Dev. Biol. 229, 263–270 (2001).

    Article  CAS  PubMed  Google Scholar 

  196. Albers, K. M. et al. Cutaneous overexpression of NT-3 increases sensory and sympathetic neuron number and enhances touch dome and hair follicle innervation. J. Cell Biol. 134, 487–497 (1996).

    Article  CAS  PubMed  Google Scholar 

  197. LeMaster, A. M. et al. Overexpression of brain-derived neurotrophic factor enhances sensory innervation and selectively increases neuron number. J. Neurosci. 19, 5919–5931 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

The support of the Medical Research Council and the Wellcome Trust is gratefully acknowledged.

Author information

Authors and Affiliations

Authors

Ethics declarations

Competing interests

The author declares no competing financial interests.

Related links

Related links

DATABASES

Entrez

α2-AR

GDNF

Lbx1

Lmx1b

NGN1

Pax2

PN3

TrkA

TrkB

TrkC

TRPV1

FURTHER INFORMATION

The London Pain Consortium

WellChild Pain Research Centre

Glossary

TYROSINE KINASE RECEPTORS

(Trk). Neurotrophic factors — nerve growth factor (NGF), neurotrophin 3 (NT3), NT4/5 and brain-derived neurotrophic factor (BDNF) — act through a family of receptor proteins, the Trk receptors. TrkA is primarily the receptor for NGF, TrkB for BDNF and NT4/5, and TrkC for NT3.

C FIBRES

Small diameter unmyelinated primary afferent sensory fibres, with small cell bodies in the dorsal root ganglion. Most are nociceptors. They divide into a neuropeptide-containing, Trk receptor-expressing group and a lectin IB4-binding group, although the functional implications of this are still unclear.

A FIBRES

Large diameter myelinated primary afferent sensory fibres, with large cell bodies in the dorsal root ganglion. The largest diameter Aβ fibres are mainly low-threshold mechanoceptors, and the smaller Aδ fibres are both mechanoreceptors and nociceptors.

EMBRYONIC DAY

(E). These are dated from the time of fertilization. Rat gestation is 21.5 days, mouse a little shorter. Rats are born relatively early in terms of CNS development and the early postnatal period is often paralleled with the final gestation of development in humans.

RECEPTIVE FIELD

The area on the body surface that, when stimulated, evokes action potentials in a given neuron.

MONOSYNAPTIC

A direct synaptic input from pre- to postsynaptic neurons with no involvement of interneurons in between.

INTERSEGMENTAL REFLEXES

Motor reponses evoked by sensory stimulation in different spinal segments.

POSTCONCEPTIONAL WEEKS

Postconceptional age is the age of a premature human infant dated from the estimated time of conception.

EXCITATORY AND INHIBITORY POSTSYNAPTIC CURRENTS

(EPSCs and IPSCs). When a neuron is voltage clamped, ion flow across a membrane can be measured as electric current while the membrane potential is controlled with a feedback amplifier. Whole-cell patch clamping has extended the technique to allow recording of excitatory and inhibitory postsynaptic currents following synaptic activation of cells in a tissue slice or even in vivo.

PERIAQUEDUCTAL GREY

An area of the brainstem that surrounds the aqueduct connecting the third and fourth ventricles. This area projects to the medullary raphe region, which, in turn, sends projections down the dorsolateral funiculus of the spinal cord to the dorsal horn. This pathway is known to strongly modulate spinal pain processing.

RECEPTOR SUBUNITS

Ion channels are generally made up of several glycoprotein subunits that surround a central pore. These subunits can confer special characteristics on a channel, such as increased calcium permeability or longer opening times. The subunits of many channels change with development, thereby altering the channel properties.

HEBBIAN WEAKENING

Hebb proposed that if a neuron, A, took part in firing another neuron, B, then a plastic change would occur in the synapse between neurons A and B, such that the connection between A and B would be strengthened. This has been extended to include the opposite effect — that is, failure to take part in firing leads to synaptic weakening.

REVERSAL POTENTIAL

The membrane potential at which chemical and electrical drive are equal and opposite, so there is no net flow of ions across the membrane. The direction of flow reverses above and below this potential.

SPARED NERVE INJURY AND CHRONIC CONSTRICTION INJURY

(SNI and CCI). Animal models of neuropathic pain aim to produce a partial denervation and/or inflammation around a nerve, as this seems to trigger characteristic allodynia or touch-evoked pain. SNI involves ligation of two nerves that supply the lateral hind paw, while leaving one intact; CCI involves tying loose ligatures around a major hindlimb nerve.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Fitzgerald, M. The development of nociceptive circuits. Nat Rev Neurosci 6, 507–520 (2005). https://doi.org/10.1038/nrn1701

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1038/nrn1701

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing