D1- and D2-receptor antagonists induce catalepsy via different efferent striatal pathways [corrected].
The D1- and D2-receptor antagonists SCH 23390 and raclopride produced a dose-dependent catalepsy as studied by a vertical grid test in the male rat. The benzodiazepine antagonist Ro 15-1788 antagonized catalepsy induced by the D2-receptor antagonist raclopride while it failed to block the action of SCH 23390. The antimuscarinic drug scopolamine reduced and the gamma-aminobutyric acid (GABA) agonist muscimol enhanced catalepsy induced by both SCH 23390 and raclopride. The results suggest that D2-antagonist-induced catalepsy is mainly mediated via activation of the strio-pallidal GABA pathways whereas D1-receptor antagonist induced catalepsy is mainly mediated via increased activity in the nigrothalamic GABA pathways.
Ogren
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Research Laboratory, Astra Alab AB, Södertälje, Sweden.
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D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D001552:Benzazepines / Q000008:administration & dosage*; D002375:Catalepsy; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D005442:Flumazenil / Q000008:administration & dosage; D007274:Injections, Intraperitoneal; D008297:Male; D009118:Muscimol / Q000008:administration & dosage; D020891:Raclopride; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000502:physiology; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012457:Salicylamides / Q000008:administration & dosage*; D012601:Scopolamine / Q000008:administration & dosage
D001552:Benzazepines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D009118:Muscimol; D005442:Flumazenil; D020891:Raclopride; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D012601:Scopolamine