钾离子诱导的、由前列腺素F2α收缩的离体脑动脉舒张。

Potassium-induced relaxation in isolated cerebral arteries contracted with prostaglandin F2alpha.

作者信息

Toda N

出版信息

Pflugers Arch. 1976 Aug 24;364(3):235-42. doi: 10.1007/BF00581761.

Abstract

In helically cut strips of canine cerebral arteries exposed to 5.4 mM [K+]o and contracted with prostaglandin F2alpha, the addition of K+ in concentrations ranging from 0.5 - 5 mM caused a dose-related relaxation. The relaxing effect of K+ was potentiated reduced [K+]o and suppressed at reduced [Na+]o. Reduction of Cl- from bathing media failed to alter the effect of K+. Removal of external Ca2+ markedly attenuated the K+-induced relaxation and increase in [Ca2+]o also attenuated the relaxation. Similar relaxation was induced by K+ in cerebral arteries from other species including humans, puppies, cats and rabbits. The addition of K+ also elicited a relaxation in peripheral arteries, including coronary, femoral, mesenteric and renal, contracted with prostaglandin, but this relaxation was markedly less than in cerebral arteries. The content of Na+ in freshly excised cerebral arteries was significantly greater than that of peripheral arteries, while the content of K+ in these arteries was not significantly different. The present study provides further evidence to support the hypothesis that an electrogenic Na+ pump is involved in the genesis of K+-induced relaxation. The Na+ pump does not appear to be fully activated at normal [K+)o of 5.4 mM in cerebral arteries.]

摘要

在暴露于5.4 mM [K⁺]ₒ并与前列腺素F2α收缩的犬脑动脉螺旋切割条中，添加浓度范围为0.5 - 5 mM的K⁺会引起剂量相关的舒张。K⁺的舒张作用在降低的[K⁺]ₒ时增强，在降低的[Na⁺]ₒ时受到抑制。从浴液中去除Cl⁻未能改变K⁺的作用。去除细胞外Ca²⁺显著减弱了K⁺诱导的舒张，而增加[Ca²⁺]ₒ也减弱了舒张。包括人类、幼犬、猫和兔子在内的其他物种的脑动脉中，K⁺也诱导了类似的舒张。添加K⁺也能使与前列腺素收缩的外周动脉，包括冠状动脉、股动脉、肠系膜动脉和肾动脉舒张，但这种舒张明显小于脑动脉。新鲜切除的脑动脉中Na⁺含量显著高于外周动脉，而这些动脉中K⁺含量无显著差异。本研究提供了进一步的证据支持以下假设：生电Na⁺泵参与了K⁺诱导舒张的发生。在脑动脉正常的5.4 mM [K⁺]ₒ时，Na⁺泵似乎未被完全激活。