Table 3.
Dopamine Release from Striatal Synaptosomes Stimulated by (+)- and (−)-PHTa
(+) PHT res α4β2 | (+) PHT sens α6β2 | (+) PHT α4β2 in α5KO* | (+) PHT α6β2 in α5KO | (−) PHT res α4β2 | (−) PHT sens α6β2 | (−) PHT α4β2 in α5KO* | (−) PHT α6β2 in α5KO | |
---|---|---|---|---|---|---|---|---|
EC50 | 0.4 μM | 0.13 μM | 2 μM | 0.20 μM | 4 μM | 4.5 μM | 0.7 μM | 2 μM |
sem | ±0.2 μM | ±0.04 μM | ±3 μM | ±0.06 μM | ±3 μM | ±0.6 μM | ±0.8 μM | ±2 μM |
maxb (% nic) | 33% | 94% | 13% | 125% | 17% | 109% | 10% | 96% |
sem | ±5% | ±18% | ±4% | ±8% | ±3% | ±25% | ±2% | ±12% |
binding Kic | 1.7 nM | 28 nM | 35 nM | 629 nM | ||||
sem | ±0.2 nM | ±3.1 nM | ±1.8 nM | ±19 nM |
EC50 from n = 3–4 experiments; DA release from mouse striatal synaptosomes; res = αCtxMII resistant (response); sens = αCtxMII sensitive (response).
Max (% nic) from n = 7–8 experiments; comparison of 10 μM nic response to 10 μM (+) PHT or 100 μM (−) PHT.
Binding Ki values from inhibition of [125I]epibatidine binding to membranes prepared from mouse cortex (α4β2 sites only) or membranes prepared from striatum and olfactory tubercle from α4KO mice (α6β2 sites only).