[The effect of antipsychotic drugs on dopamine-receptors on caudate calf].
Using radioligand receptor binding assay (RRA), dopamine receptor in the calf caudate were identified with 3H-Spiperone as radioactive ligand. The total number of maximal binding sites (Bmax), the equilibrium dissociation affinity (Kd), the concentrations of drug required to inhibited 50% specific binding (Ic50) and competitive inhibition constant (Ki) of antipsychotics in calf caudate were determined by sturative binding experiment and inhibitive binding experiment. The result showed the mean Bmax was 0.659 pmol/mg protein membrane and Kd was 0.31 nmol/L. Scatchard analysis denotes that it was hyperbole and there were two binding positions in calf caudte. Antipsychotics can inhibit 3H-Spiperone binding specifically the order of affinity constants (1/Ki) was Haloperdol and sulpiride, Chlorpromazine and Clozapin, Tranquis and Taractan. This abilities of drugs to compete with 3H-Spi binding will be used as basis of RRA for measuring blood levels of antipsychotics.
Psychiatre Institute of Mental Health of Suzhou Psychiatry of Hospital, Jiangsu.
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Guo
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001667:Binding, Competitive; D002417:Cattle; D002421:Caudate Nucleus / Q000378:metabolism*; D011869:Radioligand Assay; D011954:Receptors, Dopamine / Q000187:drug effects*; D013134:Spiperone / Q000378:metabolism
D014150:Antipsychotic Agents; D011954:Receptors, Dopamine; D013134:Spiperone