Multiquantal release of acetylcholine in mammalian ganglia

Abstract

IN the course of studies on synaptic transmission in the hypogastric ganglia of male guinea pigs it became apparent that in many ganglion cells repetitive stimulation of the hypogastric nerve at 1-Hz raised the frequency of spontaneous synaptic potentials from less than 1 min⁻¹ to about 1 s⁻¹. Many of these cells had only a single preganglionic fibre synapsing with them so that the spontaneous synaptic potentials arising from a single nerve could be readily observed. Blackman et al.¹ described large spontaneous synaptic potentials in this preparation and we decided to examine the amplitude distributions of spontaneous synaptic potentials recorded during repetitive stimulation (1Hz). Although ‘spontaneous’ synaptic potentials which were not time locked to the stimulus occurred occasionally during the evoked response, only those recorded after the membrane potential had returned to normal were selected for analysis.