[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.
He
J
J
Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005.
Zheng
Y
Y
Qu
J
J
Wang
X
X
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D002469:Cell Separation; D019204:GTP-Binding Proteins / Q000819:agonists / Q000037:antagonists & inhibitors; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D014655:Vascular Resistance
D015220:Calcium Channels; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins