Calcium channels in chromaffin cells: focus on L and T types

Acta Physiol (Oxf). 2008 Feb;192(2):233-46. doi: 10.1111/j.1748-1716.2007.01815.x. Epub 2007 Nov 16.

Abstract

Voltage-gated Ca2+ 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 Ca2+-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 Ca2+ channels is a crucial task that helps clarifying the Ca2+-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 beta-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.

Publication types

  • Review

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Channels, L-Type / physiology*
  • Calcium Channels, T-Type / physiology*
  • Calcium Signaling
  • Catecholamines / metabolism
  • Chromaffin Cells / metabolism*
  • Humans
  • Ion Channel Gating
  • Patch-Clamp Techniques

Substances

  • Calcium Channels, L-Type
  • Calcium Channels, T-Type
  • Catecholamines
  • Calcium