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 × 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 pharmacomechanical coupling, and thus producing the contraction.
|ジャーナル||Biochemical and Biophysical Research Communications|
|出版ステータス||出版済み - 4月 30 1984|
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