Pertussis toxin pretreatment enhances catecholamine secretion induced by pituitary adenylate cyclase-activating polypeptide in cultured porcine adrenal medullary chromaffin cells: a possible role of the inositol lipid cascade.
Neuropeptides
; 27(5): 269-75, 1994 Nov.
Article
em En
| MEDLINE
| ID: mdl-7862259
ABSTRACT
We determined how pertussis toxin (PTX) pretreatment alters PACAP-induced catecholamine secretion in cultured porcine adrenal medullary cells. Pretreatment of these cells with PTX (1 ng/ml for 24 h or 10 ng/ml for 6 h) markedly enhanced PACAP-induced catecholamine secretion. PTX pretreatment also produced a small increase in basal secretion and secretion in response to nicotine and carbachol, but the effect of the PACAP-induced secretion was most striking. We examined the role of the phosphoinositol cascade in potentiating the PACAP-induced catecholamine secretion by PTX and found that PACAP-induced accumulation of inositol phosphates in PTX-pretreated cells was significantly greater than that in untreated cells. Furthermore, removal of extracellular Ca2+ and addition of Ca2+ channel blockers inhibited the catecholamine secretion induced by PACAP in PTX-pretreated cells. From these results, we speculate that a PTX-sensitive G-protein tonically inhibits phospholipase C. PTX enhances the PACAP-induced secretion of catecholamine by blocking the action of this inhibitory G-protein.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neuropeptídeos
/
Fatores de Virulência de Bordetella
/
Catecolaminas
/
Sistema Cromafim
/
Medula Suprarrenal
/
Neurotransmissores
/
Toxina Adenilato Ciclase
/
Toxina Pertussis
/
Fosfatos de Inositol
Limite:
Animals
Idioma:
En
Ano de publicação:
1994
Tipo de documento:
Article