Calcium store depletion potentiates a phosphodiesterase inhibitor- and dibutyryl cGMP-evoked calcium influx in rat pituitary GH3 cells.
FEBS Lett
; 386(1): 39-42, 1996 May 13.
Article
em En
| MEDLINE
| ID: mdl-8635599
ABSTRACT
A role for cGMP in the control of capacitative Ca2+ influx was identified in rat pituitary GH3 cells. Application of 50 microM - 1 mM of the non-specific phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX), or the specific cGMP-phosphodiesterase inhibitor, zaprinast, induced a dose-dependent increase in the intracellular free Ca2+ concentration [Ca2+]i of the pituitary cell line, as assessed by video ratio imaging using fura-2. Response onset times were identical and response profiles were similar in all cells analysed. Application of 50 microM dibutyryl cGMP to GH3 cells resulted in heterogeneous Ca2+ responses, consisting of single or multiple transients with varying onset times. In all cases, increases in [Ca2+]i were predominantly due to Ca2+ influx, since no responses were detected in low Ca2+ medium, or following pre-incubation of cells with 1 microM verapamil, or nicardipine. Depleting intracellular Ca2+ stores by prior treatment of cells with 1 microM thapsigargin resulted in a dramatic potentiation in the Ca2+ influx mediated by both phosphodiesterase inhibitors and dibutyryl cGMP, suggesting that cGMP modulates a dihydropyridine-sensitive Ca2+ entry mechanism in GH3 cells which is possibly regulated by the state of filling of Ca2+ stores.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hipófise
/
Cálcio
/
Dibutiril GMP Cíclico
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Reino Unido