Interaction between inhibitory and excitatory synaptic potentials at a peripheral neurone.

1. The interaction between inhibitory and excitatory synaptic potentials in neurones lying in the submucous plexus of guinea-pig ileum has been examined. 2. It was found that during an inhibitory conductance change, electrotonic potentials were more depressed in amplitude than were excitatory synaptic potentials. 3. It is suggested that inhibitory conductance changes may have only a slight effect on the impedance seen by excitatory synaptic currents as much of the excitatory synaptic current flow is likely to be capacitive. 4. A part of the depression of excitatory synaptic potential amplitude was not associated with changes in electrical properties of neurones and it is suggested that inhibitory transmitter may reduce the release of excitatory transmitter.