TABLE 2

Potency and efficacy of drug-induced release in HEK-hDAT-hVMAT2 cells

Assays were conducted and analyses performed as described in the text. Buffer-buffer indicates that cells were incubated in buffer during [3H]DA uptake and during [3H]DA release; buffer-DHTB indicates that cells were incubated in buffer during [3H]DA uptake and with DHTB (1 μ M) during [3H]DA release. The maximal effect is the amount of [3H]DA efflux in the presence of METH or lobeline compared with cells not treated with METH or lobeline. Values are the means from at least three independent experiments, each conducted with duplicate determinations.

Buffer-Buffer
Buffer-DHTB
DHTB-Buffer
DHTB-DHTB
Treatment
EC50
 Max Effect
EC50
 Max Effect
EC50
 Max Effect
EC50
 Max Effect
μM % Release μM % Release μM % Release μM % Release
METH 33.8 ± 1.6 51 ± 1 3.2 ± 1.0 61 ± 2 14.7 ± 5.5 20 ± 2 9.71 ± 7.8 17 ± 2
Lobeline 77 ± 65 27 ± 2 ND ND ND ND ND ND
DA 26.1 ± 4.8 74 ± 2 25.1 ± 6.4 75 ± 2 45.7 ± 9.7 28 ± 7 40.4 ± 8.7 21 ± 2
p-Tyramine
1.5 ± 0.4
79 ± 2
1.5 ± 0.2
73 ± 2
3.1 ± 1.9
25 ± 6
19.7 ± 8.9
16 ± 1

  • ND, EC50 value or maximal effect were not determined due to the lack of drug effect.