Greater diversity than previously thought of chromaffin cell Ca2+ channels, derived from mRNA identification studies.
Using reverse transcription followed by PCR amplification (RT-PCR), we have identified multiple messenger RNAs encoding for the neuronal pore-forming Ca(2+) channel subunits alpha(1A) (P/Q channel), alpha(1B) (N channel), alpha(1D) (neuronal/endocrine L channel), alpha(1E) (R channel), alpha(1G-H) (T channel) and alpha(1S) (skeletal muscle L channel) in bovine chromaffin cells. mRNAs for the auxiliary beta(2), beta(3), beta(4), alpha(2)/delta and gamma(2) subunits were also identified. In agreement with these molecular data, perforated patch-clamp recordings of whole-cell Ca(2+) currents reveal the existence of functional R-type Ca(2+) channels in these cells that were previously undetected with other techniques. Our results provide a molecular frame for a much wider functional diversity of Ca(2+) channels in chromaffin cells than that previously established using pharmacological and electrophysiological approaches.
García-Palomero
E
E
Instituto Teófilo Hernando, Departamento de Farmacologia, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, 28029 Madrid, Spain.
Cuchillo-Ibáñez
I
I
García
A G
AG
Renart
J
J
Albillos
A
A
Montiel
C
C
D000818:Animals; D015220:Calcium Channels / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015220:Calcium Channels; D012333:RNA, Messenger