Dose J M, Zolman J F
Department of Psychology, University of Kentucky, Lexington 40506-0044.
Pharmacol Biochem Behav. 1994 Sep;49(1):73-8. doi: 10.1016/0091-3057(94)90458-8.
The separate and combined effects of dopamine D1 and D2 agonists on key-peck responding of young chicks for heat reinforcement were determined. In the first experiment, 1- and 4-day-old chicks (n = 96) were injected SC with either distilled water or 5 mg/kg reserpine 18 h before testing. Twenty minutes before a 24-trial autoshaping session, chicks were injected IP with either distilled water or 10 mg/kg SKF 38393 and 2 mg/kg quinpirole. Chicks receiving both dopamine agonists had enhanced key-peck responding in both pretreatment conditions. In Experiment 2, 1- and 4-day-old chicks (n = 192) of two strains received 5 mg/kg reserpine SC 18 h before testing. Twenty minutes before their autoshaping session these chicks were injected IP with either distilled water, 10 mg/kg SKF 38393, 2 mg/kg quinpirole, or 10 mg/kg SKF 38393 and 2 mg/kg quinpirole. After reserpine pretreatment, chicks of both strains responded on more trials when given both dopamine agonists compared with controls given either distilled water or single agonist treatment. No age or strain differences in key pecking were produced by the combined administration of these dopamine agonists. Therefore, functional coupling of the dopamine D1 and D2 receptors is found within 1 day after hatching in the domestic chick.
研究了多巴胺D1和D2激动剂单独及联合作用对幼雏为获得热强化而进行按键啄击反应的影响。在第一个实验中，1日龄和4日龄雏鸡（n = 96）在测试前18小时皮下注射蒸馏水或5 mg/kg利血平。在进行24次自动形成条件反射实验前20分钟，雏鸡腹腔注射蒸馏水、10 mg/kg SKF 38393或2 mg/kg喹吡罗。在两种预处理条件下，同时接受两种多巴胺激动剂的雏鸡的按键啄击反应均增强。在实验2中，两个品系的1日龄和4日龄雏鸡（n = 192）在测试前18小时皮下注射5 mg/kg利血平。在自动形成条件反射实验前20分钟，这些雏鸡腹腔注射蒸馏水、10 mg/kg SKF 38393、2 mg/kg喹吡罗或10 mg/kg SKF 38393与2 mg/kg喹吡罗的组合。利血平预处理后，与接受蒸馏水或单一激动剂处理的对照组相比，两个品系同时给予两种多巴胺激动剂的雏鸡在更多实验中做出反应。这些多巴胺激动剂联合给药未产生按键啄击的年龄或品系差异。因此，在家鸡孵化后1天内发现多巴胺D1和D2受体存在功能偶联。
