Effects of SCH 23390 and sulpiride on the behaviors evoked by amphetamine and apomorphine in adult cats.
1. The aim of the present study was to analyze whether the dopaminergic D1 and D2 receptors are involved in the production of the behaviors evoked by parenteral administration of amphetamine and apomorphine in adult cats. 2. Fifteen mongrel cats of both sexes were injected, in separate sessions, with 2.5 mg/kg of amphetamine and 2.0 mg/kg of apomorphine. The D1 receptor blocker, SCH 23390 was administered (0.3 mg/kg i.p.) and after 60 min, amphetamine and apomorphine were again injected on different days. The same procedure was carried on with sulpiride in two doses (20 and 30 mg/kg i.p.). The behaviors induced by the two dopaminergic drugs, before and after the receptor blocker administration were respectively compared. The Wilcoxon signed rank test was employed for statistical analysis. Three independent observers recorded the behaviors. 3. SCH 23390 and sulpiride produced per se hypomotility and sedation, effects that were considered when analysing the results. Some of the behaviors produced by amphetamine (pupillary dilation, head movements) were slightly modified by both receptor blockers. SCH 23390 only modified the licking behavior produced by apomorphine. In contrast, sulpiride blocked almost all the behaviors elicited by apomorphine, especially when the 30 mg/kg dose was administered. It is concluded that the behaviors produced by the 2 mg/kg dose of apomorphine are evoked by its binding to the post-synaptic dopaminergic D2 receptors and blocked by sulpiride.
Motles
E
E
Departamento de Ciencias Preclínicas Oriente, Facultad de Medicina, Universidad de Chile, Santiago.
Gomez
A
A
Tetas
M
M
Gonzalez
M
M
D000661:Amphetamine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects*; D001552:Benzazepines / Q000494:pharmacology*; D002415:Cats; D065127:Dopamine D2 Receptor Antagonists; D005260:Female; D008297:Male; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D013469:Sulpiride / Q000494:pharmacology*
D001552:Benzazepines; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride; D000661:Amphetamine; D001058:Apomorphine