Sodium ion and the neutrotransmitter-stimulated 32P labelling of phosphoinositides and other phospholipids in the iris muscle.
Biochim Biophys Acta
; 673(1): 64-74, 1981 Feb 18.
Article
em En
| MEDLINE
| ID: mdl-6110443
The effects of Na+, other cations and the neurotransmitters, acetylcholine and norepinephrine on 32Pi incorporation into phospholipids of the rabbit iris smooth muscle were investigated [1]. The basal 32P-labelling of phospholipids including phosphatidic acid, phosphatidylinositol, phosphatidylcholine, phosphatidylethanolamine and the polyphosphoinositides increased with Na+ concentration [2]. The neurotransmitter-stimulated 32P labelling of phosphatidic acid, phosphatidylinositol and phosphatidylcholine is dependent on the presence of extracellular Na+ [3]. The monovalent cation requirement for Na+ specific. Of the monovalent cations Li+, NH+4, K+, Choline+ and Tris, only Li+ partially substituted for Na+ [4]. A significant decrease in 32P labelling of phospholipids in response to acetylcholine was observed when Ca2+ and/or K+ were added to an isoosmotic medium deficient of Na+ [5]. Ouabain, which blocks the Na+-pump, inhibited the basal 32Pi incorporation into phosphatidylcholine and the acetylcholine-stimulated 32P labelling of phosphatidic acid, phosphatidylinositol and phosphatidylcholine [6]. It was suggested that phosphoinositide breakdown is associated with Ca2+ influx as we have previously reported (Akhtar, R.A. and Abdel-Latif, A.A. (1978) J. Pharmacol. Exp. Ther. 204, 655-668) and that the enhanced 32P-labelling of phosphoinositides could be associated with Na+ outflux, via the Na+-pump mechanism.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfolipídeos
/
Sódio
/
Iris
/
Neurotransmissores
/
Músculo Liso
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1981
Tipo de documento:
Article