Table 1

Nicotinic α7 receptors expressed in Xenopusoocytes: parameter values of fitted dose-response curves for selected drugs used in this study

ActivationInhibition
EC50 (K)Hill Coefficient (H)Relative Efficacy (a/āACh)IC50 (K)Hill Coefficient (H)
μM μM
ACh153  (113, 209)0.91  ± 0.101.00  ± 0.04N.D.N.D.
Nicotine76  (50, 117)1.09  ± 0.220.69  ± 0.040.65  (0.58, 0.73)−1.53  ± 0.11
AR-R 1777927  (14, 50)0.99  ± 0.220.98  ± 0.090.17  (0.16, 0.19)−1.65  ± 0.13
DMAC12  ( 6, 28)0.86  ± 0.250.33  ± 0.030.10  (0.09, 0.12)−1.70  ± 0.29
DHβENo effect20  (17, 24)−1.30  ± 0.12
MLANo effect0.0005  (0.0004, 0.0006)−1.46  ± 0.14

EC50 and IC50 values (K in eq. 1) are given as mean (lower 95% confidence limit, upper 95% confidence limit), and the values of the other parameters (H,a) are given as mean ± S.E. The efficacy (a, maximum of agonist dose-response curves) is expressed as a fraction of the mean efficacy of ACh, āACh. For ACh, nicotine, MLA, and DHβE, the results are similar to those reported by Briggs et al. (1995), Briggs and McKenna (1998), and Chavez-Noriega et al. (1997).

• N.D., not determined.