Dendritic spikes in normal spinal motoneurons of cats.
A spike of about 2 ms in duration and 3-8 mV in amplitude (D-spike) was produced by peripheral nerve (biceps semitendinosus, tibial and sciatic nerves) and dorsal root (L7 and S1) stimulation in normal spinal motoneurons of cats in a decerebrate, non-anesthetized state. The strength of the hyperpolarizing current to abolish the D-spike was always greater than that to abolish the IS-spike. The D-spike triggered the IS-spike at a level more depolarized than that at which the M-spike triggered the IS-spike. An inhibitory postsynaptic potential, which inhibited the IS-spike, could not inhibit the D-spike. Two different D-spikes, as distinguished by a difference in threshold, could occur in the same motoneuron. These results suggested that the D-spike was dendritic in origin.
Fujita
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Y
Department of Physiology, Nippon Medical School, Tokyo, Japan.
D000200:Action Potentials; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002415:Cats; D003712:Dendrites / Q000502:physiology*; D004558:Electric Stimulation; D009046:Motor Neurons / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology