GTPγS及GDPβS对SHRSP内脏阻力血管平滑肌钙通道的影响

目的 研究Ｇ蛋白激动剂ＧＴＰγＳ和抑制剂ＧＤＰβＳ对卒中易感型自发性高血压大鼠（ＳＨＲＳＰ）及常压大鼠肠系膜动脉Ａ４－Ａ５分支阻力血管平滑肌钙通道的影响。方法 应用膜片箝全细胞钡电流方式。结果 （１）ＧＴＰγＳ使ＳＨＲＳＰ和Ｗｉｓｔａｒ两种大鼠阻力血和平滑肌全细胞峰值钡电流明显增加,且ＳＨＲＳＰ大鼠显著大于Ｗｉｓｔａｒ大鼠。ＧＤＰβＳ则可报制两种大鼠的全细胞峰值钡电流,对于ＳＨＲＳＰ大鼠的帽程度显

Effects of GTP gamma S and GDP beta S on calcium channels of resistance vascular smooth muscle cells in SHRsp

OBJECTIVE: To investigate the effects of GTP gamma S and GDP beta S on the whole-cell barium currents of voltage-dependent calcium channels (VDC) of the vascular smooth muscle cells (VSMC) from the A4-A5 branches in SHRSP mesenteric artery. METHODS: Using the whole-cell Ba2+ current recording of the patch clamp technique. RESULTS: (1) GTP gamma S, a G-protein agonist, increased whole-cell Ba2+ currents both of SHRSP and Wistar, but SHRSP with a higher ratio of amplitude change than Wistar. In addition, GTP gamma S shifted D infinity to right both in SHRSP and Wistar, but D infinity shifted more in SHRSP than that in Wistar. (2) GDP beta S, a G-protein antagonist, decreased whole-cell Ba2+ currents both of SHRSP and Wistar, but SHRSP with a higher inhibition ratio of amplitude change than Wistar. In addition, GDP beta S shifted F infinity to right and in SHRSP shifted more than control under HP = -80 mV. CONCLUSIONS: The G-protein mechanism may promote Ca2+ influx and contribute to the increase of peripheral resistance during hypertension.