Figure 6.

Gβ antibody and Gβγ subunit infusion did not affect mIcat properties. Carbachol in the presence of Gβ antibodies (1 : 200 v v⁻¹) was applied at 50 μM concentration every 5 min (a) or for a long period (b) to measure steady-state I–V curves estimated by applying slow voltage ramp from 80 to −120 mV. Below are the superimposed I–V curves from the experiments in the panels above measured at 5 min intervals starting 20 min after breakthrough (a) and at 30 s interval starting at 35 min after breakthrough (b) For leak correction, the I–V curve measured immediately before carbachol application was subtracted. (c) Lack of effect of Gβγ dimer on mIcat generation obtained in a control (top) and in Gβγ -treated cell (bottom). (d) Mean data fitted by the Hill equation (control, n=17; Gβγ, n=13). Best-fit parameters were as follows: I_max 0.920 and 0.804 nA; EC₅₀ 2.4 and 2.4 μM; Hill slope 1.3 and 1.1 for control and Gβγ -treated groups, respectively.