Prestwich_1995_Br.J.Pharmacol_115_147

Reference

Title : Effects of GTP gamma S on muscarinic receptor-stimulated inositol phospholipid hydrolysis in permeabilized smooth muscle from the small intestine - Prestwich_1995_Br.J.Pharmacol_115_147
Author(s) : Prestwich SA , Miyazaki H , Bolton TB
Ref : British Journal of Pharmacology , 115 :147 , 1995
Abstract :

1. Smooth muscle fragments from the longitudinal layer of the small intestine of the guinea-pig were permeabilized with Staphylococcus aureus alpha toxin (alpha-toxin) and used to investigate the role of G-protein activation in the regulation of muscarinic acetylcholine receptor (AChR)-stimulated inositol phospholipid hydrolysis. 2. The efficiency of alpha-toxin permeabilization was estimated by the release of [3H]-2-deoxyglucose ([3H]-2DG) after prior loading or lactate dehydrogenase (LDH) enzyme release from the smooth muscle fragments. 3. In alpha-toxin-permeabilized smooth muscle, but not in non-permeabilized muscle, GTP gamma S induced time- and concentration-dependent increases in labelled inositol phosphates. Carbachol (CCh) increased labelled inositol phosphates in both permeabilized and non-permeabilized muscle, although the increases were greater in non-permeabilized smooth muscle. The response to 100 microM CCh was severely reduced by 0.5 microM atropine. 4. In permeabilized muscle the effects of GTP gamma S or CCh on inositol phosphate levels were reduced by treatment with pertussis toxin (PTX) and completely inhibited by GDP beta S. 5. GTP gamma S caused a concentration-dependent inhibition of the CCh-induced increases in the levels of labelled inositol phosphates. Dibutyryl cyclic AMP or Sp-cAMPs (adenosine-3',5'-cyclic phosphorothiolate-Sp) reduced the effects of CCh on inositol phosphate levels. 6. The results suggest that muscarinic AChR activation induces inositol phospholipid hydrolysis via more than one G-protein in this smooth muscle and that several mechanisms may contribute to the modulation of both stimulatory and inhibitory responses observed.

PubMedSearch : Prestwich_1995_Br.J.Pharmacol_115_147
PubMedID: 7647969

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Citations formats

Prestwich SA, Miyazaki H, Bolton TB (1995)
Effects of GTP gamma S on muscarinic receptor-stimulated inositol phospholipid hydrolysis in permeabilized smooth muscle from the small intestine
British Journal of Pharmacology 115 :147

Prestwich SA, Miyazaki H, Bolton TB (1995)
British Journal of Pharmacology 115 :147