Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9882308 | Archives of Biochemistry and Biophysics | 2005 | 9 Pages |
Abstract
Chromaffin cells of the adrenal medulla receive cholinergic input from the splanchnic nerve. Upon sympathetic activity, chromaffin cells fire action potentials that open voltage-gated calcium channels and evoke the exocytic release of catecholamines. Catecholamines then regulate homeostatic processes such as cardiac output and vascular tone. Thus control of the Ca2+ influx in chromaffin cells represents a target for the regulation of multiple physiological functions. Previous reports utilized square pulse depolarizations to quantify the proportional exocytic response as a function of Ca2+ channel subtype. In this study, we use perforated patch voltage clamp and action potential waveforms to depolarize cells in situ. We analyze Ca2+ current components under conditions that match the dynamic native cell behavior. This approach revealed a greater role for P/Q-type calcium channels in evoked exocytosis than previously reported. Thus, the P/Q-type channels represent a more important control point for the regulation of catecholamine-dependent processes than previously believed.
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Authors
Shyue-An Chan, Luis Polo-Parada, Corey Smith,