title: Inositol-1,4,5-trisphosphate releases calcium from skinned cultured smooth muscle cells.
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.
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D046508:Culture Techniques; D007295:Inositol Phosphates / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D013403:Sugar Phosphates / Q000494:pharmacology*
chemical_list: D007295:Inositol Phosphates; D013403:Sugar Phosphates; D002110:Caffeine; D002118:Calcium