title: Inositol 1,4,5-trisphosphate releases Ca2+ from intracellular store sites in skinned single cells of porcine coronary artery.
abstract: Effects of inositol 1,4,5- trisphosphate , extracted from human erythrocyte ghosts, on Ca2+ release from intracellular store sites were studied in saponin-treated single muscle cells of the porcine coronary artery. Application of micromolar concentrations of inositol 1,4,5- trisphosphate released Ca2+ from the intracellular non-mitochondrial store sites, within 1 min. However, when the concentrations of free Ca2+ were over 1.5 X 10(-6) M, the release of Ca2+ by this agent was inhibited. The Ca2+ releasing mechanism differed from that seen with A23187, therefore this release of Ca2+ from store sites was not due to Ca2+ ionophore actions. This agent may play the role of messenger in increasing the cytosolic Ca2+, provoking pharmaco-mechanical coupling, and thus producing the contraction.
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000032:analysis; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000494:pharmacology*; D007700:Kinetics; D009119:Muscle Contraction; D012503:Saponins / Q000494:pharmacology; D013403:Sugar Phosphates / Q000494:pharmacology*; D013552:Swine
chemical_list: D007295:Inositol Phosphates; D012503:Saponins; D013403:Sugar Phosphates; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium