Department of Pharmacology, Quillen College of Medicine, East Tennessee State University, P.O. Box 70577, Johnson City, TN 37614, USA.
Neurotox Res. 2012 Feb;21(2):231-5. doi: 10.1007/s12640-011-9268-5. Epub 2011 Aug 19.
Quinpirole-induced vertical jumping is a phenomenon first observed in rats treated from birth, once a day for 21 days or more, with the dopamine D₂ receptor agonist quinpirole. This quinpirole-induced behavioral sensitization is known as a priming process. To determine whether dopaminergic innervation influenced this priming phenomenon, groups of rats were lesioned at 3 days after birth with the neurotoxin 6-hydroxydopamine (6-OHDA; 67 μg in each lateral ventricle; desipramine pretreatment, 20 mg/kg ip, 1 h). Rats were additionally treated daily from birth with quinpirole HCl (3.0 mg/kg ip, salt form). Controls received saline vehicle in place of 6-OHDA and/or quinpirole. When rats were placed in individual observation cages (1 h acclimation) starting at 20 days after birth, acute quinpirole treatment produced vertical jumping in the quinpirole-primed group; and the effect persisted through the twenty-ninth day. In rats additionally lesioned with 6-OHDA, vertical jumping was enhanced at 20, 24, 26/27, and 28/29 day--with there being as much as a 32-fold increase in vertical jumping versus the group that was primed with quinpirole, but not lesioned with 6-OHDA. This finding indicates that an ontogenetic 6-OHDA lesion enhances quinpirole-induced vertical jumping in rats and that dopaminergic innervation may normally exert a suppressive effect on vertical jumping.
喹吡罗诱导的垂直跳跃是一种首先在出生后每天接受多巴胺 D₂ 受体激动剂喹吡罗处理 21 天或更长时间的大鼠中观察到的现象。这种喹吡罗诱导的行为敏化被称为引发过程。为了确定多巴胺能神经支配是否影响这种引发现象，在出生后第 3 天用神经毒素 6-羟多巴胺（6-OHDA；每个侧脑室 67 μg；去甲丙咪嗪预处理，20 mg/kg ip，1 h）对大鼠进行分组损伤。大鼠从出生起每天还接受盐酸喹吡罗（3.0 mg/kg ip，盐形式）治疗。对照组用生理盐水代替 6-OHDA 和/或喹吡罗。当大鼠从出生后第 20 天开始被放置在单独的观察笼中（1 h 适应期）时，急性喹吡罗处理在喹吡罗引发组中产生垂直跳跃；并且该效果持续到第 29 天。在另外用 6-OHDA 损伤的大鼠中，垂直跳跃在第 20、24、26/27 和 28/29 天增强-与用喹吡罗引发但未用 6-OHDA 损伤的组相比，垂直跳跃增加了 32 倍。这一发现表明，发育性 6-OHDA 损伤增强了大鼠中喹吡罗诱导的垂直跳跃，并且多巴胺能神经支配可能对垂直跳跃正常发挥抑制作用。
