The effects of physostigmine on synaptic transmission in the inferior mesenteric ganglion of guinea‐pigs

Abstract

1. Synaptic potentials were recorded with intracellular electrodes from cells in the inferior mesenteric ganglion of the guinea‐pig. 2. Half‐widths of the synaptic potentials recorded fell into two groups: type L cells had long synaptic potentials (11·6–15·2 msec) and low thresholds (14·6 mV mean), type S cells had short synaptic potentials (6·1–9·3 msec) and high thresholds (29·9 mV mean). 3. Physostigmine (1·2 × 10−6 M) caused a significant increase in the half‐width of both types of synaptic potential. 4. Physostigmine caused a significant increase in the half‐width of spontaneous synaptic potentials and an increase in their amplitude. 5. Repetitive preganglionic stimulation, in the prese..