Endothelin-1-induced depolarization and hyperpolarization in submandibular ganglion neurons.

The effects of endothelin-1 were studied in vitro on neurons in the hamster submandibular ganglion, using the intracellular microelectrode technique. Endothelin (1 microM) caused a depolarization (5.5 +/- 1.2 mV) followed by a hyperpolarization (8.5 +/- 2.8 mV) of the membrane potential. Membrane conductance was increased during the endothelin-induced depolarization and was decreased during the endothelin-induced hyperpolarization. The endothelin-induced depolarization was depressed (mean 43.6%) in a Krebs solution containing zero calcium and high magnesium. The results suggested that the predominant component of the depolarization was mediated by calcium ions. The calcium-insensitive component of depolarization was carried by chloride ions. Endothelin-induced slow rhythmic hyperpolarizations were probably induced by a decrease in chloride ion conductance.