Greater diversity than previously thought of chromaffin cell Ca2+ channels, derived from mRNA identification studies

Abstract

AbstractUsing reverse transcription followed by PCR amplification (RT-PCR), we have identified multiple messenger RNAs encoding for the neuronal pore-forming Ca2+ channel subunits α1A (P/Q channel), α1B (N channel), α1D (neuronal/endocrine L channel), α1E (R channel), α1G-H (T channel) and α1S (skeletal muscle L channel) in bovine chromaffin cells. mRNAs for the auxiliary β2, β3, β4, α2/δ and γ2 subunits were also identified. In agreement with these molecular data, perforated patch-clamp recordings of whole-cell Ca2+ currents reveal the existence of functional R-type Ca2+ channels in these cells that were previously undetected with other techniques. Our results provide a molecular frame for a much wider functional diversity of Ca2+ channels in chromaffin cells than that previously established using pharmacological and electrophysiological approaches