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Calcium channels in chromaffin cells: focus on L and T types
Author(s) -
Marcantoni A.,
Carabelli V.,
Comunanza V.,
Hoddah H.,
Carbone E.
Publication year - 2008
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2007.01815.x
Subject(s) - chromaffin cell , exocytosis , voltage dependent calcium channel , secretion , adrenal medulla , microbiology and biotechnology , biology , catecholamine , cell type , membrane potential , stimulation , neurotransmitter , endocrinology , medicine , calcium , neuroscience , cell , biochemistry , central nervous system
Voltage‐gated Ca 2+ channels (Cav) are highly expressed in the adrenal chromaffin cells of mammalian species. Besides shaping action potential waveforms, they are directly involved in the excitation–secretion coupling underlying catecholamine release and, possibly, control other Ca 2+ ‐dependent events that originate near the membrane. These functions are shared by a number of Cav channel types (L, N, P/Q, R and T) which have different structure–function characteristics and whose degree of expression changes remarkably among mammalian species. Understanding precisely the functioning of each voltage‐gated Ca 2+ channels is a crucial task that helps clarifying the Ca 2+ ‐dependent mechanisms controlling exocytosis during physiological and pathological conditions. In this paper, we focus on classical and new roles that L‐ and T‐type channels play in the control of chromaffin cell excitability and neurotransmitter release. Interestingly, L‐type channels are shown to be implicated in the spontaneous autorhythmicity of chromaffin cells, while T‐type channels, which are absent in adult chromaffin cells, are coupled with secretion and can be recruited following long‐term β‐adrenergic stimulation or chronic hypoxia. This suggests that like other cells, adrenal chromaffin cells undergo effective remodelling of membrane ion channels and cell functioning during prolonged stress conditions.