Fig. 4.

Voltage-independent inhibition by CK and M4. (A) GABA (2 µM) was first applied and pre-treatment of CK (100 µM) or M4 (100 µM) before GABA application inhibited I_GABA in oocytes expressing ρ1 GABA_C receptors. The inhibitory degrees were very similar at -30 mV and -120 mV of membrane potential. (B) Voltage-independent inhibition of I_GABA in GABA_C receptors by CK and M4. Values were obtained from the receptors in the absence or presence of 100 µM CK and M4 at the indicated membrane holding potentials. The observed effects of CK and M4 were correlated with membrane potential. No significant effects were noted for CK (r²=0.28, p>0.31) and M4 (r²=0.10, p>0.44).