A study of ionic conductances involved in plateau potential activity in putative vasopressinergic neurons in primary cell culture.

Vasopressin neurons in hypothalamic cell culture display regenerative calcium-dependent plateau potentials. The present study was undertaken to investigate the mechanisms underlying their time course and periodicity. Intracellular recordings showed that the duration of the plateaux was controlled by a progressive activation of a voltage- and calcium-dependent potassium conductance, but not by a progressive inactivation of calcium conductances. The refractory period appeared to be due to a calcium-dependent potassium conductance activated by membrane potential depolarization.