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Silent glutamatergic synapses and nociception in mammalian spinal cord

Nature volume 393, pages 695–698 (1998)Cite this article

Abstract

Neurons in the superficial dorsal horn of the spinal cord are important for conveying sensory information from the periphery to the central nervous system1,2. Some synapses between primary afferent fibres and spinal dorsal horn neurons may be inefficient or silent3. Ineffective sensory transmission could result from a small postsynaptic current that fails to depolarize the cell to threshold for an action potential or from a cell with a normal postsynaptic current but an increased threshold for action potentials. Here we show that some cells in the superficial dorsal horn of the lumbar spinal cord have silent synapses: they do not respond unless the holding potential is moved from −70 mV to +40 mV. Serotonin (5-hydroxytryptamine, 5-HT), an important neurotransmitter of the raphe–spinal projecting pathway, transforms silent glutamatergic synapses into functional ones. Therefore, transformation of silent glutamatergic synapses may serve as a cellular mechanism for central plasticity in the spinal cord.

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Figure 1: Silent glutamatergic synapses in the lumbar spinal cord.
Figure 2: Biphasic modulation induced by 5-HT.
Figure 3: Transformation of silent synapses into functional synapses by 5-HT or DOI.
Figure 4: Dependence on postsynaptic G proteins and intracellular Ca2+.

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Acknowledgements

We thank R. W. Tsien and J. H. Steinbach for reviewing the manuscript, N. Gautam for discussion, P. Mason for communication of unpublished data, and G. Maccaferri, J. Li, E. T. Kavalali and X. D. Yang for technical advice. This work was supported in part by a grant from the NIDA.

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Authors and Affiliations

  1. Department of Anesthesiology, Campus Box 8054

    Ping Li & Min Zhuo

  2. Department of Anatomy and Neurobiology, Washington University in St Louis, St Louis, 63110, Missouri, USA

    Ping Li & Min Zhuo

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  1. Ping Li
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  2. Min Zhuo
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Correspondence to Min Zhuo.

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Li, P., Zhuo, M. Silent glutamatergic synapses and nociception in mammalian spinal cord. Nature 393, 695–698 (1998). https://doi.org/10.1038/31496

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