Abstract
WHEN recorded intracellularly, the soma-dendritic spike potential of cat spinal motoneurones (SD spike1) is followed by a brief phase of depolarization which reverses to a prolonged hyperpolarization (duration, 60–250 msec.)1,2. Investigation of after-hyperpolarization has yielded three experimental results which conjointly led to the hypothesis that it is due to a prolonged increase in permeability to potassium ions3: there is an increased membrane conductance; when the membrane potential is changed by applying current intracellularly, the size of the after-hyperpolarization is increased by depolarization and decreased by hyperpolarization, being reduced to zero at about 20-mV. hyperpolarization; this equilibrium potential is shifted in the depolarizing direction by an electrophoretic injection of sodium ions into the motoneurone, which would of course result in a decrease of intracellular potassium ion concentration. In the present investigation on after-hyperpolarization, successive spike potentials of a cat motoneurone resulted in a considerable summation of after-hyperpolarizations and there was a corresponding increase in the membrane conductance.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Brock, L. G., Coombs, J. S., and Eccles, J. C., J. Physiol., 122, 429 (1953).
Eccles, J. C., Eccles, R. M., and Lundberg, A., J. Physiol., 142, 275 (1958).
Coombs, J. S., Eccles, J. C., and Fatt, P., J. Physiol., 130, 291 (1955).
Frank, K., and Fuortes, M. G. F., J. Physiol., 134, 451 (1956).
Coombs, J. S., Curtis, D. R., and Eccles, J. C., J. Physiol., 145, 505 (1959).
Ito, M., Jap. J. Physiol., 7, 297 (1957).
Ritchie, J. M., and Straub, R. W., J. Physiol., 136, 80 (1957).
Greengard, P., and Straub, R. W., J. Physiol., 144, 442 (1958).
Straub, R. W., J. Physiol., 159, 19P (1961).
Kuno, M., J. Physiol., 149, 374 (1959).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
ITO, M., OSHIMA, T. Temporal Summation of After-Hyperpolarization following a Motoneurone Spike. Nature 195, 910–911 (1962). https://doi.org/10.1038/195910a0
Issue Date:
DOI: https://doi.org/10.1038/195910a0
This article is cited by
-
Triplet firing origin in human motor units: emerging hypotheses
Experimental Brain Research (2016)
-
Analysis of motoneuron responses to composite synaptic volleys (computer simulation study)
Experimental Brain Research (2012)
-
Time Structure of Impulsation of Spinal Motoneurons of Cats under Conditions of Realization of the Stretch Reflex
Neurophysiology (2011)
-
Measurement and nature of firing rate adaptation in turtle spinal neurons
Journal of Comparative Physiology A (2005)
-
Afterhyperpolarization?firing rate relation of turtle spinal neurons
Journal of Comparative Physiology A (2005)
Comments
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.