Slow Synaptic Responses in Autonomic Ganglia

摘要: The known synaptic potentials present a considerable range of durations, but at least in the vertebrates maximum durations are limited to an order hundred milliseconds or so (Eccles 1964). It has become clear, however, that postsynaptic responses with about 1 25 seconds can be elicited by preganglionic impulses sympathetic ganglia. This presents up 100 fold greater than longest (PSP) otherwise known. One slow ganglionic is surface-negative, facilitatory potential which may termed “slow EPSP”. other surface-positive, presumably hyperpolarizing potential, for it not been practicable thus far obtain direct evidence inhibitory nature. Although excitatory (EPSP) appears generated same ganglion cells as initial fast EPSP, extraordinary latency 250 msec and mediated second type receptor acetylcholine (ACh) isatropine-sensitive muscarinic nature rather well nicotinic, curare-sensitive type. Since long duration EPSP ganglia evidently function single level terminations (i. e. “monosynaptic” type), these PSP’s assume especial significance neuro-physiological processes general. Suitable intracellular studies have yet achieved, partly because fibrous impenetrability mammalian