Figure 8.

αM-MIIIA block of αβε nAChR (A), and washout kinetics from αβε AChR (B) and αβδε nAChR (C). These experiments were done essentially as in Figure 7. A. αM-MIIIJ concentration–response curve for block of αβε nAChR (see Table 2 for IC₅₀). The data points follow a trajectory steeper than their fit to a Langmuir isotherm (solid curve), the significance of which remains to be determined. B, C. αM-MIIIJ washout curves from αβε (B) and αβδε (C) nAChRs. Solid line is the best-fit single-exponential curve with a k_off of 0.80 min⁻¹ (95% C.I. of 0.7–0.9) for αβε, and 0.76 min⁻¹ (95% C.I. of 0.4–1.2) for αβδε. Data points represent mean ± S.E. (n = 3 for panels A and B; and n = 6 for panel C, from aggregate of open circles in Figure 9B,E below).