The changes in the amount and function of G proteins of resistance vascular smooth muscle from the rats with hypertension and congestive heart failure

1)。用免疫组织化学方法检测了4、10和20周龄自发性高血压大鼠、年龄匹配的对照组、Wistar-京都大鼠和一肾一夹继发性高血压大鼠外周阻力血管和主动脉中G蛋白的定位和丰度。自发性高血压大鼠在4周(高血压发病前)、10周和20周龄时，提睾肌动脉内GI或Gs免疫反应阳性物质的浓度显著低于同龄Wistar-京都大鼠。而自发性高血压大鼠与Wistar-京都大鼠、继发性高血压大鼠的阻力动脉与正常对照大鼠相比，GI和Gs的丰度均无显著差异。高血压前期SHR的β2-AR-Gs系统的舒张性较SHR降低，SHR的Alpha2-GI系统的收缩功能也较WKY减少。自发性高血压大鼠外周阻力血管内膜GI和Gs浓度和功能的早期变化可能反映了受体介导的信号转导功能受损，并可能参与高血压的发病机制。2)充血性心力衰竭大鼠阻力小动脉α2-GI系统功能较假手术对照组降低。对Gs和Gi蛋白浓度的进一步研究以及Gs的功能研究正在进行中。

1). The localization and abundance of G proteins in a peripheral resistance vessel and the aorta were determined immunohistochemically in the 4-, 10- and 20-week-old spontaneously hypertensive rats, age-matched control, Wistar-Kyoto rats, and one-kidney, one-clip secondary hypertensive rats. The concentrations of Gi- or Gs-like immunoreactivity in the smooth muscle of the cremaster artery were significantly lower in spontaneously hypertensive rats at 4 weeks (before the onest of hypertension), 10 weeks and 20 weeks of age, as compared with the age-matched Wistar-Kyoto rats. In contrast, no significant differences were detected in the abundance of Gi or Gs between the aortic smooth muscle of spontaneously hypertensive rats and Wistar-Kyoto rats, or between resistance artery smooth muscle of the secondary hypertensive and control rats. The dilation via beta2-AR-Gs system was decreased in prehypertensive SHR compared with SHR.The constriction via alpha2-Gi system also decreased in SHR compared with WKY.These early changes in the concentration and function of Gi and Gs in the smooth muscle of peripheral resistance vessels in spontaneously hypertensive rats may reflect impaired receptor-mediated signal transduction and may be involved in pathogemesis of hypertensin.2) The function of alpha2-Gi system of resistance small artery was decreased in the rats with congestive haert failure compared with sham-operated control rats. Further study for concentartion of Gs and Gi protein and functional study of Gs are going now.