TABLE 3

Functional effects of nicotinic compounds on high (HS) and low (LS) ACh sensitivity α4β2 nAChRs

Concentration-response data were obtained and fitted to one- or two-component sigmoidal equations as described under Materials and Methods. Data were obtained from at least five oocytes from two different donors. Imax and nH values are presented as mean ± S.E.M.

HS α4β2 nAChR LS α4β2 nAChR
EC50 (95% CI) I/ImaxAChnH EC50 (95% CI) I/ImaxAChnH
μM
Ach 4 (3.6-5.7) 1 ± 0.004 0.84 ± 0.02 88 (71-109) 1.1 ± 0.005 0.94 ± 0.01
Nicotine 1 (0.8-1.3) 0.28 ± 0.01 0.78 ± 0.07 34 (23-50) 0.62 ± 0.03 0.83 ± 0.07
Epibatidine 0.02 (0.01-0.03) 0.6 ± 0.02 0.86 ± 0.09 1.3 (0.4-4) 2.2 ± 0.2 0.54 ± 0.1
TC-2559 2 (1-3) 2.6 ± 0.2 0.76 ± 0.2 2.7 (1.2-6.1) 0.22 ± 0.02 0.83 ± 0.2
A-85380 0.03 (0.02-0.04 1.3 ± 0.06 1 ± 0.1 3.3 (2-5) 1.6 ± 0.06 0.58 ± 0.05
Cytisine N.D. N.E. 12 (4-34) 0.22 ± 0.03 0.74 ± 0.04
3-Br-Cytisine 0.008 (0.005-0.01) 0.2 ± 0.009 0.8 ± 0.1 0.05 (0.04-0.08) 0.29 ± 0.01 0.73 ± 0.04
5-I-Cytisine N.D. N.E. 3.2 (2-4) 0.53 ± 0.01 0.99 ± 0.08
5-Br-Cytisine N.D. N.E. 13 (10-16) 0.31 ± 0.01 1.7 ± 0.4
5-Cl-Cytisine N.D. N.E. 14 (94-192) 0.21 ± 0.01 1.50 ± 0.3
  • N.D., not determined; N.E., no effect detected at highest concentration tested (1 mM).