Fig. 9.

Agonist dependencies of the stationary current inhibition predicted by models 1–5. The degree of the stationary current inhibition, 1 −I_BS/I_CS, rises with the agonist concentration for models 1–3, decreases for model 4, and is constant for model 5. The agonist dependencies predicted by models 1, 2, and 3 coincided at [B] = 28, 2.6, and 1.1K_d, respectively, and were well fitted with Equation 2 (solid line). The values of the fitting parameters were as follows: A₁= 0, A₂ = 0.515 ± 0.002, [A]₀ = 8.18 ± 0.15 μm, andn_Hill = 1.39 ± 0.04. The fitting of the agonist dependence predicted by model 4 at [B] = 2.5K_d (solid line) gave the following values of the fitting parameters:A₁ = 0.733 ± 0.003,A₂ = 0.515 ± 0.001, [A]₀ = 17.9 ± 0.6 μm, andn_Hill = 1.13 ± 0.03. The degree of the stationary current inhibition for model 5 did not depend on the agonist concentration and was equal to 0.515 at [B] = 1.1K_d. The values of parameters were as follows: P₀ = 0.09,τ_wash = 30 msec, andk₂ = 1000 sec⁻¹.