Fig. 4.

Activated Gαq subunits inhibit TASK-3 in excised inside-out macropatches. (A) Currents recorded from a representative multichannel macropatch excised from an HEK293 cell transfected with TASK-3. Time series of currents (at +60 mV) from patches exposed sequentially to halothane, G protein activation buffer, nonactivated Gαq-GDP, and Gαq preactivated with GTPγS. The boxed region is expanded in the Center, and ramp currents under the indicated conditions provided in the Right. (B) TASK-3 currents from a patch exposed to GTPγS-loaded Gαi before Gαq-GTPγS. (C) TASK-3 currents from a patch exposed to Gαq-GTPγS during prolonged treatment with the PLC inhibitor U73122 (5 μM). (D) Averaged inhibition (% of control, ± SEM) from macropatches treated with various G protein subunits. Of those tested, only Gαq-GTPγS inhibited TASK-3 currents.