Fig. 5.
Influence of Gqα protein overexpression on D1R + D2LR–mediated calcium mobilization. (A) HEK293T cells were transfected with D1R + D2LR with and without Gqα or with Gqα alone (D1R + D2R EC50 = 168.3 nM, ECmax = 100%; D1R + D2R + Gq EC50 = 16.8 nM, ECmax = 300.1%). (B) HEK293T cells were transfected with D1R + D2LR, D1R, or D2R with and without Gqα (D1R + Gq EC50 = 10.3 nM, ECmax = 152.2%). Twenty-four hours later, cells were plated in 384-well plates and assayed the following day for calcium mobilization after stimulation by the indicated concentrations of DA. Data are expressed as a percentage of control maximum DA stimulation for D1R + D2LR alone and are representative of two or three independent experiments performed with the same assay conditions on different days. Error bars indicate S.E.M. from multiple wells within the representative experiment.