Inositol-1,4,5-trisphosphate releases calcium from skinned cultured smooth muscle cells.

Department of Pharmacology, University of Miami School of Medicine, Miami, Florida 33101 USA
Biochemical and Biophysical Research Communications (Impact Factor: 2.41). 08/1985; 130(1):270-4. DOI: 10.1016/0006-291X(85)90412-7
Source: PubMed

ABSTRACT We examined the effects of inositol-1,4,5-trisphosphate on 45Ca uptake and 45Ca efflux in the saponin skinned primary cultured rat aortic smooth muscle cells. 10 microM inositol-1,4,5-trisphosphate induced a rapid (half time less than 10 sec) and large quantity of Ca release in both 45Ca uptake and 45Ca efflux in the skinned cells preloaded with 1 microM free Ca. Dose response curves showed that 100 microM inositol-1,4,5-trisphosphate produced a maximal Ca release of 97.3% of the MgATP dependent 45Ca uptake or 289 mumoles/liter cells, which was much greater than the maximal caffeine induced Ca release and would be sufficient to produce maximal tension.

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