Fig. 4.

Effect of heterologous overexpression of mutant Gβ1 and Gα_tr on basal facilitation and NE-mediated Ca²⁺ current inhibition. Superimposed Ca²⁺ current traces evoke with the double-pulse voltage protocol (bottom of E) in the absence (bottom traces) and presence (top traces) of 10 μm NE for wild-type β1γ2- and Gα_tr- (A), β1(80)γ2- (B), β1(80)γ2- and Gα_tr- (C), β1(80,88,89)γ2- (D), and β1(80,88,89)γ2 and Gα_tr-expressing (E) neurons.F, Summary graphs of mean ± SEM basal facilitation and Ca²⁺ current inhibition for neurons expressing wild-type and mutant Gβ1γ2 alone or combined with Gα_tr. Final concentration of cDNA injected was 10 ng/μl per subunit. Basal facilitation and Ca²⁺ current inhibition were calculated as described in Figure1E. *p < 0.05 versus control; **p < 0.01 versus control.Numbers in parentheses indicate the number of experiments.