| Abstract: | Synaptic activity of neurons giving diphasic excitatory-inhibitory potentials in response to orthodromic stimulation was recorded intracellularly. In response to stimulation of nerves by a single short pulse these neurons developed only the excitatory component of the diphasic potential, but with a longer stimulus a prolonged inhibitory phase, partly suppressing the initial excitatory component, was added. The excitatory phase appeared only when the resting potential reached a certain level. In their response to repetitive stimulation, neurons with a diphasic potential are divided into habituating and nonhabituating. The diphasic potential can also arise in response to application of acetylcholine to the soma of these neurons. It is postulated that this potential reflects the response of different receptors of the postsynaptic membrane to the same mediator. Prolonged poststimulus hyperpolarization can be obtained after repetitive orthodromic or direct stimulation of some neurons. However, as analysis of the results showed, poststimulus hyperpolarization is endogenous in origin and differs in its mechanisms from the diphasic potential.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 5, No. 2, pp. 193–200, March–April, 1973. |
