McDougall S A, Crawford C A, Nonneman A J
Department of Psychology, California State University, San Bernardino 92407.
Psychopharmacology (Berl). 1993;111(2):225-32. doi: 10.1007/BF02245528.
In general, preweanling and adult rats respond similarly when challenged with competitive dopamine (DA) agonists or antagonists. In contrast, results using a noncompetitive antagonist suggest that the D1 and D2 receptor systems of preweanling and adult rats differ in some critical way. To further assess this phenomenon, the behavioral effects of irreversible receptor blockade were assessed across 8 days in NPA (a nonselective DA agonist), quinpirole (a D2 agonist), or SKF 38393 (a D1 agonist) treated 17-day-old rat pups. The irreversible antagonist N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) did not block the locomotor activity and rearing of NPA- or quinpirole-treated rat pups, nor did EEDQ reduce SKF 38393-induced grooming. Moreover, pretreatment with EEDQ appeared to potentiate the normal increases in locomotor activity and rearing produced by NPA, but only when D2 receptors were not protected by a previous injection of sulpiride (a D2 antagonist). Taken together, these results are consistent with the presence of large reserves of D1 and D2 receptors in the preweanling rat pup.
一般来说，断奶前大鼠和成年大鼠在受到竞争性多巴胺（DA）激动剂或拮抗剂刺激时反应相似。相比之下，使用非竞争性拮抗剂的结果表明，断奶前大鼠和成年大鼠的D1和D2受体系统在某些关键方面存在差异。为了进一步评估这一现象，在8天内对用NPA（一种非选择性DA激动剂）、喹吡罗（一种D2激动剂）或SKF 38393（一种D1激动剂）处理的17日龄幼鼠进行不可逆受体阻断的行为效应评估。不可逆拮抗剂N - 乙氧羰基 - 2 - 乙氧基 - 1,2 - 二氢喹啉（EEDQ）并未阻断NPA或喹吡罗处理的幼鼠的运动活动和竖毛行为，EEDQ也未减少SKF 38393诱导的梳理行为。此外，EEDQ预处理似乎增强了NPA引起的运动活动和竖毛行为的正常增加，但仅在D2受体未被先前注射的舒必利（一种D2拮抗剂）保护时才会如此。综上所述，这些结果与断奶前幼鼠中存在大量D1和D2受体储备一致。
