Multiple calcium pathways induce the expression of SNAP-25 protein in chromaffin cells

Garcia-Palomero, E; Montiel, C; Herrero, CJ; Garcia, AG; Alvarez, RM; Arnalich, FM; Renart J.; Lara, H; Cárdenas AM

Abstract

Incubation of bovine adrenal chromaffin cells in high K+ (38 mM) during 24-48 h enhanced 2.5 to five times the expression of SNAP-25 protein and mRNA, respectively. This increase was reduced 86% by furnidipine 9(an L-type Ca2+ channel blocker) but was unaffected by either w-conotoxin GVIA (an N-type Ca2+ channel blocker) or w-agatoxin IVA (a P/Q-type Ca2+ channel blocker). Combined blockade of N and P/Q channels with w-conotoxin MVIIC did, however, block by 76% the protein expression. The inhibitory effects of furnidipine were partially reversed when the external Ca2+ concentration was raised from 1.6 to 5 mM. These findings, together with the fact that nicotinic receptor activation or Ca2+ release from internal stores also enhanced SNAP-25 protein expression, suggest that an increment of cytosolic Ca2+ concentration ([Ca2+],), rather than its source or Ca2+ entry pathway, is the critical signal to induce the protein expression, The greater coupling between L-type Ca2+ channels and protein expression might be due to two facts: (a) L channels contributed 50% to the global [Ca2+], rise induced by 38 mM K+ in indo-1-loaded chromaffin cells and (b) L channels undergo less inactivation than N or P/Q channels on sustained stimulation of these cells.

Más información

Título según WOS: Multiple calcium pathways induce the expression of SNAP-25 protein in chromaffin cells
Título según SCOPUS: Multiple calcium pathways induce the expression of SNAP-25 protein in chromaffin cells
Título de la Revista: JOURNAL OF NEUROCHEMISTRY
Volumen: 74
Número: 3
Editorial: Wiley
Fecha de publicación: 2000
Página de inicio: 1049
Página final: 1058
Idioma: English
URL: http://doi.wiley.com/10.1046/j.1471-4159.2000.0741049.x
DOI:

10.1046/j.1471-4159.2000.0741049.x

Notas: ISI, SCOPUS