Zarrindast M R, Amin R
Department of Pharmacology, Medical School, University of Tehran, Iran.
Psychopharmacology (Berl). 1992;106(1):67-70. doi: 10.1007/BF02253590.
The possible involvement of subtypes of dopamine (DA) receptors in pecking induced by apomorphine (APO) in chicks was studied. D-1/D-2 agonist APO dose-dependently induced pecking in chicks. The APO response was decreased in animals pretreated with either the D-2 receptor antagonist sulpiride or the D-1 receptor antagonist SCH 23390. The inhibitory effects of both antagonists were also dose dependent. The pecking induced by APO was completely inhibited in animals pretreated with a combination of SCH 23390 and sulpiride and was potentiated with reserpine. Single administration of D-2 agonist quinpirole or D-1 agonist SKF 38393 did not induced pecking, although quinpirole, but not SKF 38393 caused considerable response in reserpine or reserpine + alpha-methyl-p-tyrosine (AMPT)-treated animals. When quinpirole was administered with SKF 38393, a slight pecking response was shown. This was also potentiated in reserpine or reserpine + AMPT-treated chicks. The results may indicate that both D-1 and D-2 DA receptors are involved in pecking induced by APO, and reserpine treatment caused the sensitization of the D-2 receptors for the induction of pecking in chicks.
研究了多巴胺（DA）受体亚型在阿扑吗啡（APO）诱导雏鸡啄食行为中的可能作用。D-1/D-2激动剂APO能剂量依赖性地诱导雏鸡啄食。用D-2受体拮抗剂舒必利或D-1受体拮抗剂SCH 23390预处理的动物，其对APO的反应降低。两种拮抗剂的抑制作用也呈剂量依赖性。用SCH 23390和舒必利联合预处理的动物，APO诱导的啄食行为完全被抑制，而利血平则使其增强。单独给予D-2激动剂喹吡罗或D-1激动剂SKF 38393不会诱导啄食，尽管喹吡罗（而非SKF 38393）在利血平或利血平+α-甲基-对酪氨酸（AMPT）处理的动物中引起了相当大的反应。当喹吡罗与SKF 38393一起给药时，出现了轻微的啄食反应。在利血平或利血平+AMPT处理的雏鸡中，这种反应也增强了。结果可能表明，D-1和D-2 DA受体均参与了APO诱导的啄食行为，利血平处理导致雏鸡D-2受体对啄食诱导的敏感性增加。
