Fig. 5.

Dihydropyridine binding to the expressed Ca²⁺ channels. A, Equilibrium binding curves for [³H]-PN200-110 in cells transfected with α_1C alone or in combination with the α₂δ or the δ subunits. Symbolsrepresent mean values of specific DHP binding of duplicate samples in one representative experiment. Data were fit with a one-site ligand-binding equation of the form: y = [L] · Cap/(K_D + [L]), where L is the concentration of free ligand, Cap is the maximum bound ligand, andK_D is the dissociation constant.B, Comparison of specific [³H]-PN200-110 binding to microsomes of tsA201 cells transfected with α_1C alone or in combination with α₂δ or δ subunits. Binding assays were performed with 1 nm [³H]-PN200-110. Data are given as mean ± SE, and the number of separate experiments is indicated in parentheses. Asterisksdenote significant differences (p < 0.05).