IN the acute spinal animal L-3,4-dihydroxyphenyl-alanine (DOPA) gives a marked increase in the flexor reflex which can be evoked on pinching the skin1,2. An electrophysiological analysis revealed that DOPA depresses the transmission of single volleys from the flexor reflex afferents to motoneurones and to primary afferents3,4. DOPA is more effective in depressing the path from the flexor reflex afferents to primary afferents than to motoneurones. Hence there was the possibility that DOPA, by eliminating the negative feed-back of presynaptic inhibition (the primary afferent depolarization in the flexor reflex afferents), might give more effective transmission to motoneurones despite its inhibitory action on this path3. However, further experiments have shown that this explanation is not correct.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Get just this article for as long as you need it
Prices may be subject to local taxes which are calculated during checkout
Magnusson, T., and Rosengren, E., Experientia, 19, 229 (1963).
Carlsson, A., Magnusson, T., and Rosengren, E., Experientia, 19, 359 (1963).
Andén, N. E., Lundberg, A., Rosengren, E., and Vyklický, Experientia, 19, 654 (1963).
Andén, N. E., Jukes, M. G. M., and Lundberg, A., Nature, 202, 1222 (1964).
Eccles, R. M., and Lundberg, A., Arch. ital. Biol., 97, 199 (1959).
Wall, P. D., J. Physiol. (Lond.), 142, 1 (1958).
Eccles, J. C., Magni, F., and Willis, W. D., J. Physiol. (Lond.), 160, 62 (1962).
Rights and permissions
About this article
Cite this article
ANDÉN, N., JUKES, M., LUNDBERG, A. et al. A New Spinal Flexor Reflex. Nature 202, 1344–1345 (1964). https://doi.org/10.1038/2021344b0
This article is cited by
Transspinal stimulation and step training alter function of spinal networks in complete spinal cord injury
Spinal Cord Series and Cases (2021)
Effects of flexor reflex afferent stimulation on the soleus H reflex in patients with a complete spinal cord lesion: evidence for presynaptic inhibition of Ia transmission
Experimental Brain Research (1990)
Effect of repetitive stimulation of the locus coeruleus on spinal inhibition evoked in cats by activation of flexor reflex afferents
Late long-lasting discharges in hind limb motor nerves and their connection with the locomotor rhythm in thalamic immobilized cats
Effect of local depression of inhibition on electrical activity of the spinal cord
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.