Electrical excitability of cultured adrenal chromaffin cells.

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Abstract
Adult human and gerbil adrenal medullary cells were maintained in dissociated cell culture and studied by microelectrode penetration. In the best recordings, chromaffin cell transmembrane potentials exceeded -50 mV. Chromaffin cells were capable of generating all-or-nothing overshooting action potentials, similar to those generated by sympathetic neurons. The action potentials were blocked by tetrodotoxin (TTX, 10-6 g/ml.) but were not blocked by removal of Ca or by CoCl2 (10 mM). The action potentials are probably generated by a Na mechanism. Chromaffin cells are depolarized by the iontophoretic application of acetylcholine (ACh). This depolarization was accompanied by an increased membrane conductance and could trigger action potentials. Action potentials also were found in cells in fresh slices of gerbil adrenal medullae.