Table 1 Comparison of the affinities (Ki values, nM) of various receptor antagonists at dopamine D2 and D4 receptors with their protective effects (at 10-6M) on hippocampal neurons (expressed in % of MTT values vs control group).
D2 subtype Affinity (Ki, nM) | D4 subtype Affinity (Ki, nM) | Neuroprotective activity (% vs control, MTT values) | |
|---|---|---|---|
(+)-butaclamol | 0.8 | 40 | 464 |
Clozapine | 36–190 | 1.6–40 | 340 |
Chlorpromazine | 0.66–1.5 | 1.15–37 | 320 |
Domperidone | 0.30 | ND | 299 |
Haloperidol | 0.35–1 | 0.84–5.1 | 271 |
(±)-sulpiride a | 9.2–15 | 52–1000 | 199 |
L-741,742 | > 1700 | 3.5 | 186 |
Risperidone | 0.3–5.9 | 0.25–16 | 162 |
Haloperidol metabolite | > 10000 | ND | 108 |
Raclopride | 0.64–1.8 | 237–620 | 110 |
Remoxipride | 30–2000 | 2800–3690 | 108 |
U 99194 | 2281 | > 10000 | 100 |