Properties of dopamine antagonists for high- and low-magnitude Ca2+ response at the recombinant D2short receptor in CHO-K1 cells
| Ligand | DA (10 μM) | |||
|---|---|---|---|---|
| Antagonism of High-Magnitude Ca2+Response | Reversal of Low-Magnitude Ca2+ Response | |||
| Capacity | pIC50 | Capacity | pIC50 | |
| % | % | |||
| Clozapine | 8 ± 2 (39 ± 13)1-a | −2 ± 1 (29 ± 5)1-a | ||
| (−)-Butaclamol | 11 ± 8 (−1 ± 0.4)1-a | 0 ± 2 (2 ± 1)1-a | ||
| Chlorpromazine | 14 ± 4 (54 ± 31-b | 16 ± 3 (55 ± 8)1-b | 6.21 ± 0.111-b | |
| (+)-UH 232 | 15 ± 2 (42 ± 5)1-b | −2 ± 1 (56 ± 6)1-a | 6.22 ± 0.041-a | |
| Olanzapine | 26 ± 6 (55 ± 3)1-b | 6.09 ± 0.091-b | 15 ± 3 (45 ± 4)1-b | 6.04 ± 0.121-b |
| (−)-Sulpiride | 33 ± 6 (55 ± 11)1-b | 6.35 ± 0.191-b | 30 ± 2 (82 ± 4)1-b | 6.51 ± 0.091-b |
| Fluphenazine | 65 ± 5 | 6.17 ± 0.14 | 1 ± 2 (61 ± 8)1-a | 6.13 ± 0.141-a |
| S 14066 | 68 ± 5 | 6.43 ± 0.28 | 64 ± 4 | 6.03 ± 0.02 |
| Haloperidol | 69 ± 3 | 6.48 ± 0.19 | 79 ± 4 | 6.22 ± 0.18 |
| Risperidone | 75 ± 3 | 7.92 ± 0.00 | 68 ± 5 | 6.18 ± 0.19 |
| Domperidone | 85 ± 2 | 6.90 ± 0.10 | 41 ± 4 (87 ± 4)1-b | 6.31 ± 0.051-b |
| (+)-Butaclamol | 93 ± 3 | 6.44 ± 0.18 | 6 ± 2 (49 ± 4)1-b | 6.03 ± 0.021-b |
| Bromerguride | 95 ± 1 | 7.26 ± 0.04 | 27 ± 3 (82 ± 5)1-b | 6.53 ± 0.191-b |
| Tropapride | 99 ± 0.5 | 8.12 ± 0.08 | 100 | 6.74 ± 0.10 |
| Nemonapride | 100 ± 1 | 7.57 ± 0.05 | 91 ± 5 | 6.41 ± 0.25 |
DA-mediated high- and low-magnitude Ca2+ responses were measured as described under Experimental Procedures.Antagonist and reversal capacity, and pIC50 values were determined as described under Experimental Procedures.Capacity values represent mean values ± S.E.M. of 5 to 18 independent transfection experiments, each one performed in quadruplicate. Values in parentheses represent capacity values (%) for either antagonism or reversal of 0.1 or 1 μM DA-mediated high- and low-magnitude Ca2+ responses.