Nakayama K
Arch Int Pharmacodyn Ther. 1985 Jan;273(1):117-30.
Pig coronary strips were exposed to sucrose-, mannitol- or NaCl-hyperosmolar Tyrode solution and to a solution containing varying concentrations of calcium or potassium ions. In the hyperosmolar solutions obtained by addition of sucrose, mannitol and NaCl to 540, 556 and 308 mM, respectively, the resting tension was increased, while isometric tension development upon electrical stimulation was decreased. Increase in the Ca2+ and K+ concentrations augmented the phasic contraction upon electrical stimulation and produced a rise in the resting tension. The contractions produced by hyperosmolarity, high Ca2+ and K+ were susceptible to metabolic blockades, hypoxia, low temperature and glucose deprivation. The increase in the resting tension produced by hyperosmolarity was resistant to verapamil and persisted in Ca2+-free hyperosmolar solution, while the effects of additional Ca2+ and K+ on the phasic and tonic contractions were inhibited by verapamil. The results suggest that tension development in coronary artery produced by hyperosmolarity does not require verapamil-sensitive entry of Ca2+, but Ca2+ presumably supplied from intracellular stores.
将猪冠状动脉条暴露于蔗糖、甘露醇或氯化钠高渗的台氏液以及含有不同浓度钙离子或钾离子的溶液中。在分别添加蔗糖、甘露醇和氯化钠至540、556和308 mM所得到的高渗溶液中，静息张力增加，而电刺激时等长张力的产生减少。钙离子和钾离子浓度的增加增强了电刺激时的相性收缩，并使静息张力升高。高渗、高钙和高钾所产生的收缩对代谢阻断、缺氧、低温和葡萄糖缺乏敏感。高渗所导致的静息张力增加对维拉帕米有抗性，并且在无钙高渗溶液中持续存在，而额外的钙离子和钾离子对相性和强直性收缩的作用则被维拉帕米抑制。结果表明，高渗所导致的冠状动脉张力产生并不需要对维拉帕米敏感的钙离子内流，而是可能由细胞内储存库提供钙离子。
