Evidence that the H+ electrochemical gradient across membranes of chromaffin granules is not involved in exocytosis.
J Biol Chem
; 258(12): 7506-13, 1983 Jun 25.
Article
em En
| MEDLINE
| ID: mdl-6863252
ABSTRACT
The possibility that the large H+ electrochemical potential of chromaffin granules, the secretory granules of adrenal medullary chromaffin cells, plays an important role in exocytosis was investigated in cultures of chromaffin cells from bovine adrenal medulla. Methylamine uptake into the cells, [gamma-31P]phosphate nmr of ATP within intracellular chromaffin granules, O2 consumption of intracellular mitochondria, and MgATP-stimulated catecholamine uptake into chromaffin granules isolated from cultured chromaffin cells were assessed to determine whether various manipulations altered the H+ electrochemical gradients of intracellular chromaffin granules or mitochondria. Catecholamine secretion was not significantly altered by ammonium, methylamine, nigericin, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, or dicyclohexylcarbodiimide under conditions when the pH of intracellular chromaffin granules was reduced or when granular or mitochondrial processes were uncoupled from H+ electrochemical gradients. The data indicate that the H+ electrochemical gradient across the chromaffin granule membrane does not play a role in exocytosis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Grânulos Cromafim
/
Sistema Cromafim
/
Medula Suprarrenal
/
Membranas Intracelulares
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1983
Tipo de documento:
Article