Figure 4.

cDNA transfection ratio has no effect on α4β3δ receptor stoichiometry. (A) Inhibition by 1 μM Zn²⁺ of GABA EC₅₀ currents for αβ or αβδ receptors expressed following transfection with one of three α:β:δ cDNA ratios: 1:1:1, 1:1:10 and 10:1:10 (n = 4–5; mean ± SEM). The total amount of cDNA used for each transfection was 4 μg. (B) GABA concentration–response curves for αβδ (filled circles) or αβδ_m (open circles) transfected with the α:β:δ cDNA ratios: 1:1:1, 1:1:10 and 10:1:10. The Hill equation was fitted to each data set using a non-linear least-squares method (continuous lines).