Voltammetric studies of basal and electrically evoked cathecolamine release from long‐term cultures of chromaffin cells

Abstract

Previous in vitro studies have revealed basal and evoked release from cultures of chromaffin cells (CC). However no basal and evoked release of catecholamines from long‐term permanent cultures of CC have been studied. The objectives of the present study were to compare basal and evoked release of catecholamines from these type of cultures and to achieve a long period of survival of permanent microcultures. CC were obtained from adult bovine adrenal glands and plated (50 k cells, n = 3; 100 k cells, n = 9) in microculture dishes with a platinum sputter‐coated base. Basal and electrical evoked release (50 Hz, 100–250 mA/15 s) from CC microcultures were recorded using fast cyclic voltammetry with carbon‐fiber microelectrodes at different intervals of time (20, 40, 60, 90 days). Cell counts at each time period were assessed using an inverted microscope. After at least 120 days, CC were fixed, marked for TH, PNMT, and the nuclei stained. CC count decreased slightly over the entire period of culture. The basal release of electroactive compounds from the long‐term microcultures was always present although a decrease was associated with the decrease in CC count. The electrical stimulation of cells did show an increased release (best between 200 and 250 mA stimuli) in the nanomolar range compared to that of the basal release. Confocal microscopy of labeled cultures revealed that most of the CC present were adrenergic and noradrenergic. This study shows that permanent populations of CC microcultures can be maintained long‐term and the catecholamine release enhanced with electrical stimulation.