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.

[1]  B. Katz.  Experimental Evidence for a Non-Conducted Response of Nerve to Subthreshold Stimulation , 1937 .

[2]  A. Hodgkin,et al.  A quantitative description of membrane current and its application to conduction and excitation in nerve , 1952, The Journal of physiology.

[3]  Y Fujita,et al.  Activity of dendrites of single Purkinje cells and its relationship to so-called inactivation response in rabbit cerebellum. , 1968, Journal of neurophysiology.

[4]  B LIBET,et al.  The behaviour of chromatolysed motoneurones studied by intracellular recording , 1958, The Journal of physiology.

[5]  D. H. Paul.  The physiology of nerve cells , 1975 .

[6]  K. Walton,et al.  Ionic mechanisms underlying the firing properties of rat neonatal motoneurons studied in vitro , 1986, Neuroscience.

[7]  P. G. Nelson,et al.  Anomalous rectification in cat spinal motoneurons and effect of polarizing currents on excitatory postsynaptic potential. , 1967, Journal of neurophysiology.

[8]  D. Kernell,et al.  Delayed depolarization and the repetitive response to intracellular stimulation of mammalian motoneurones , 1963, The Journal of physiology.

[9]  B. Walmsley,et al.  The effect of polarizing currents on unitary Ia excitatory post‐synaptic potentials evoked in spinal motoneurones. , 1976, The Journal of physiology.

[10]  C. Terzuolo,et al.  AN ANALYSIS OF INTRA‐ VERSUS EXTRACELLULAR POTENTIAL CHANGES ASSOCIATED WITH ACTIVITY OF SINGLE SPINAL MOTONEURONS * , 1961, Annals of the New York Academy of Sciences.

[11]  P. G. Nelson,et al.  Delayed depolarization in cat spinal motoneurons. , 1967, Experimental neurology.

[12]  J. Eccles,et al.  The interpretation of spike potentials of motoneurones , 1957, The Journal of physiology.

[13]  R. Llinás,et al.  Electrophysiological properties of dendrites and somata in alligator Purkinje cells. , 1971, Journal of neurophysiology.

[14]  Y. Fujita,et al.  Dendritic activities of spinal motoneurones in pigs and rabbits enhanced through chronic stimulation of a dorsal root. , 1987, The Journal of physiology.

[15]  R Llinás,et al.  Enhancement of synaptic transmission by dendritic potentials in chromatolysed motoneurones of the cat , 1970, The Journal of physiology.

[16]  J. Eccles,et al.  The electrical properties of the motoneurone membrane , 1955, The Journal of physiology.

[17]  A. Hodgkin,et al.  The Subthreshold Potentials in a Crustacean Nerve Fibre , 1938 .