Fig. 2.

Effect of CK and M4 on I_GABA in oocytes expressing the ρ1 GABA_C receptor. (A) GABA (2 µM) was first applied and then was co- or pre-treated with CK (100 µM). Co-treatment of CK with GABA and pre-treatment of CK before GABA application inhibited I_GABA in oocytes expressing ρ1 GABA_C receptors. (B) GABA (2 µM) was first applied and then co- or pre-treated with M4 (100 µM). Co-treatment of M4 with GABA and pre-treatment of M4 before GABA application inhibited I_GABA in oocytes expressing ρ1 GABA_C receptors. The resting membrane potential of oocytes was approximately -35 mV and oocytes were voltage clamped at a holding potential of -80 mV prior to drug application. Traces are representative of 8~12 separate oocytes from 3 different frogs. (C) Summary of percent inhibition by CK and M4 of I_GABA calculated from the average of the peak inward current elicited by GABA alone before CK and M4 and the peak inward current elicited by GABA alone after co- and pre-treatment of CK and M4 with GABA. Each point represents the mean±S.E.M. (n=9~12 from 3 different frogs). ^*p <0.05 as compared to co-treatment of CK and M4, and ^#p<0.05 as compared to CK.