Effects of stimulation on the multiquantal spontaneous synaptic potentials in guinea pig hypogastric ganglia.

Loss frequency (0.5-2 Hz) stimulation of the preganglionic nerve produced calcium ion (Ca2+)-dependent increases in the frequency of spontaneous synaptic potentials recorded from guinea-pig hypogastric ganglion cells. The increased frequency was accompanied by a marked increase in the proportion of multiquantal spontaneous potentials and this was also dependent on extracellular Ca2+. The latter effect was interpreted as an increase in the degree of bursting within the spontaneous release process, supporting the hypothesis that the bursting is related to the cytoplasmic Ca2+ concentration.