Figure 4.

Strychnine block of muscle AcChoRs is noncompetitive. Dose-response curve for AcCho-current in the absence (filled circle) and presence (open circles) of strychnine measured in the same oocyte. Continuous lines represent least squares fits to the Hill equation I_[AcCho] = I_max·[AcCho]ⁿ/([AcCho]^nH + EC₅₀^nH), where I_[AcCho] is the AcCho dose-dependent current amplitude, I_max is the amplitude of the control AcCho-current, EC₅₀ is the half-excitatory concentration of AcCho, and nH is the Hill coefficient. (Inset) Membrane currents elicited by two concentrations of AcCho superfused on one oocyte expressing muscle α₁β₁γδ AcChoRs. After 4 min, AcCho and 10 μM strychnine were coapplied.