The potencies and efficacies of dopaminergic antagonists in inhibiting constitutive adenylyl cyclase activity
| Compound | EC50 | Maximal Inhibition |
|---|---|---|
| μM | % | |
| (+)-Butaclamol | 0.021 ± 0.007 | 96.1 ± 5.9 |
| Chlorpromazine | 0.099 ± 0.059 | 99.3 ± 1.2 |
| Clozapine | 0.821 ± 0.406 | 95.5 ± 6.2 |
| Fluphenazine | 0.026 ± 0.012 | 78.9 ± 6.8 |
| cis-Flupenthixol | 0.035 ± 0.025 | 96.5 ± 3.6 |
| Haloperidol | 0.408 ± 0.169 | 76.9 ± 6.8 |
Membrane protein (50 μg) obtained from PC2 cells expressing D1A dopamine receptors was incubated at 30°C for 10 min with the test drugs in the presence of 1 μCi [α-32P]ATP and formed [32P]cAMP was assessed. The effects of the dopaminergic antagonists (+)-butaclamol, chlorpromazine, clozapine, fluphenazine, cis-flupenthixol, and haloperidol on constitutive adenylyl cyclase activity were tested at concentrations ranging from 0.1 nM to 100 μM. The potencies and efficacies for inhibition of constitutive adenylyl cyclase activity were calculated from the data presented in Fig. 2A using nonlinear regression analysis.