GTPγS-Induced Ca²⁺ Activated Cl⁻ Currents: Its Stable Induction by Gqα Overexpression in Xenopus Oocytes

Abstract

In native Xenopus oocytes, injection of guanosine 5'-O-(3-thiotriphosphate) (GTPγS) (30 mM, 5 nl) did not induce Cl⁻ current in 11 out of 22 oocytes. Injection of increased concentration of GTPγS (100 mM, 5 nl) into the oocytes induced Cl⁻ currents in 16 out of 17 oocytes; however, the size of the induced currents was extremely varied. In oocytes overexpressing Gqα, GTPγS (30 mM, 5 nl) faithfully evoked Ca²⁺-activated Cl⁻ currents. These results indicate that heterogeneous expression of Gqα in Xenopus oocytes provides a useful system for studying the functional roles of Gqα in regulating cellular events.