Synaptic potentials in nerve cells of the stellate ganglion of the squid.

1. Intracellular recordings were made from nerve cells in the stellate ganglion of the squid.2. Stimulation of the preganglionic nerve evoked excitatory or inhibitory synaptic potentials, or a combination of both. Antidromic stimulation of the stellar nerves also evoked excitatory and inhibitory potentials in the cells. With both types of stimulation the synaptic potentials were built up of contributions from several axons indicating considerable convergence of excitatory and inhibitory inputs on the cells.3. Inhibitory, as well as excitatory, miniature synaptic potentials were recorded from the cells even after impulse activity had been blocked by tetrodotoxin.4. Glutamate applied iontophoretically to some cells produced a depolarization of their membranes. In other cases glutamate evoked a hyperpolarizing potential. Application of glutamate caused a decrease in the amplitude of excitatory synaptic potentials.