TABLE 2

Zinc potentiation of wild-type and mutant neuronal nAChRs

Data is presented as the ratio of potentiation of the mutant receptors to potentiation of wild-type receptors expressed in the same batch of oocytes (mean ± S.E.M., n = 3–13). For α4β4, Zn2+ concentration was 100 μM. For α4β2, Zn2+ concentration was 50 μM. The overall value for potentiation of wild-type α4β4 was 579 ± 13% of ACh alone (n = 48). The overall value for potentiation of wild-type α4β2 was 241 ± 14% of ACh alone (n = 15). Fit maximum potentiation, EC50, and Hill coefficient (nH) were determined by fitting the data in Fig. 6 to a Hill equation (mean ± S.E.M., n = 4–6).

Receptor Potentiation (Mutant/WT) Fit Maximum Potentiation EC50nH
% of ACh μM
WT α4β4 1.00 660 ± 53 26 ± 6 1.8 ± 0.5
α4H2E β4 1.08 ± 0.14
α4H2A β4 0.97 ± 0.09
α4E59A β4 0.73 ± 0.05*** 454 ± 23*** 17 ± 2 1.6 ± 0.4
α4H61N β4 0.75 ± 0.10* 444 ± 32*** 23 ± 5 1.5 ± 0.4
α4H104D β4 1.21 ± 0.21
α4H104A β4 0.90 ± 0.11
α4H109L β4 1.18 ± 0.15
α4H162G β4 0.45 ± 0.04*** 301 ± 19*** 18 ± 4 1.5 ± 0.3
α4-2 β4 1.23 ± 0.03*
α4 β4C75S 0.94 ± 0.06
α4 β4H157R 0.97 ± 0.13
α4 β4D195A 0.88 ± 0.05
α4 β4H469Y 0.82 ± 0.03* 451 ± 16*** 21 ± 2 1.4 ± 0.2
α4-2 β4C75S (pseudo-WT) 0.93 ± 0.06
WT α4β2 1.00
α4E59A β2 0.58 ± 0.13†††
α4H162G β2 0.38 ± 0.05†††
  • ** P < 0.01, significant difference in potentiation compared with wild-type α4β4.

  • * P < 0.05, significant difference in potentiation compared with wild-type α4β4.

  • *** P < 0.001, significant difference in potentiation compared with wild-type α4β4.

  • ††† P < 0.001, significant difference in potentiation compared with wild-type α4β2.