GTP结合蛋白增强了α毒素通透的子宫平滑肌对Ca2+的收缩反应。

GTP-binding protein amplifies contractile responses of alpha-toxin-permeabilized uterine smooth muscle to Ca2+.

Suga O, Oishi K, Uchida M K

Department of Molecular Pharmacology, Meiji College of Pharmacy, Tokyo, Japan.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1993 Jan;104(1):187-91. doi: 10.1016/0742-8413(93)90133-6.

Abstract

alpha-toxin of Staphylococcus aureus readily permeabilized rat uterine smooth muscle after incubation for a short time. 2. The permeabilized muscle responded to Ca2+ dose-dependently and repeatedly in the same manner. 3. The threshold concentration of Ca2+ for contraction was 0.1-0.3 microM and the maximal contraction was achieved with 1 or 3 microM Ca2+. 4. GTP gamma S or GTP augmented the contractile response to Ca2+. 5. GDP beta S or GDP suppressed the contraction. 6. The role of GTP-binding protein in sensitization of Ca(2+)-induced contractile response of smooth muscle is discussed.

摘要

金黄色葡萄球菌的α毒素在短时间孵育后能迅速使大鼠子宫平滑肌通透性增加。2. 通透性增加的肌肉对Ca2+呈剂量依赖性反应，且能以相同方式反复反应。3. 引起收缩的Ca2+阈值浓度为0.1 - 0.3微摩尔，1或3微摩尔Ca2+可使收缩达到最大值。4. GTPγS或GTP增强了对Ca2+的收缩反应。5. GDPβS或GDP抑制收缩。6. 讨论了GTP结合蛋白在平滑肌Ca(2+)诱导收缩反应致敏中的作用。