TABLE II.

Inhibition of Adult Human nAChRs by Tacrine

Membrane potential	IC 50	n
mV	μM
−70	4.6 ± 0.23	1.4 ± 0.08
−110	2.5 ± 0.24	1.5 ± 0.15
−150	1.6 ± 0.09	1.9 ± 0.19

The parameters and error estimates are derived from fits of Eq. 2 to the data shown in Fig. 2. Each fitted parameter is expressed ± SE. IC ₅₀ is the concentration of tacrine that produces a 50% reduction in P _open. n is the Hill coefficient.