细胞松弛素对妊娠大鼠离体子宫纵肌机械和膜反应的影响及其与EGTA抗性收缩的关系。

Effects of cytochalasins on the mechanical and membrane responses in the isolated longitudinal myometrium of pregnant rat with reference to the EGTA-resistant contraction.

作者信息

Osa T, Maruta K

机构信息

Department of Physiology, Yamaguchi University School of Medicine, Japan.

出版信息

Jpn J Physiol. 1988;38(6):869-86. doi: 10.2170/jjphysiol.38.869.

DOI:10.2170/jjphysiol.38.869

PMID:3150474

Abstract

Effects of cytochalasins B and D (CB, CD) were examined for the contractions of the longitudinal myometrium of pregnant rat exposed to Krebs solution, 40 mM K Krebs, and Ca-free (40 mM K) solution containing 5 mM Mg. The Ca-free contraction was evoked by applying 3 mM ATP. Application of CB caused a prompt inhibition of the contractions: 3 microM CB depressed the twitch contraction generated in Krebs solution by 12%, the K-contracture by 6%, and the ATP-induced contraction in the Ca-free solution by 59%. CD (3 microM) depressed the K-contracture by 31%, and the ATP-induced contraction in the Ca-free solution by 81%. CB and CD in 3 microM hyperpolarized the membrane and depressed the generation of action potential. From the above results, it was discussed that depressant effects of cytochalasins on twitch contractions in Krebs solution are at least in part due to the depression of membrane excitability, whereas contractions evoked in high K solutions are depressed by cytochalasins due to their effects on cytoskeleton.

摘要

研究了细胞松弛素B和D（CB、CD）对暴露于 Krebs 溶液、40 mM K Krebs 溶液以及含5 mM Mg的无钙（40 mM K）溶液中的妊娠大鼠子宫纵肌收缩的影响。无钙收缩是通过施加3 mM ATP诱发的。应用CB可迅速抑制收缩：3 microM CB使在Krebs溶液中产生的抽搐收缩降低12%，钾挛缩降低6%，在无钙溶液中ATP诱导的收缩降低59%。CD（3 microM）使钾挛缩降低31%，在无钙溶液中ATP诱导的收缩降低81%。3 microM的CB和CD使膜超极化并抑制动作电位的产生。根据上述结果，讨论了细胞松弛素对Krebs溶液中抽搐收缩的抑制作用至少部分归因于膜兴奋性的降低，而在高钾溶液中诱发的收缩因细胞松弛素对细胞骨架的作用而受到抑制。