不同训练时段影响甲基苯丙胺诱导的大鼠自身给药行为的形成

目的 观察不同时间给予甲基苯丙胺(METH)对大鼠形成自身给药行为的影响。方法 通过6 d的FR1程序训练合格的大鼠进入实验。按照4个给药时间8:00-8:30,10:00-10:30,11:30-12:00及16:00-16:30和2个给药因素生理盐水和METH 0.05 mg·kg^-1分为8组,持续8 d。在自身给药装置中FR1程序记录给药次数和有效鼻触和无效鼻触次数。结果 与同一给药时间的溶剂对照组相比,METH组大鼠自身给药的次数及有效鼻触次数显著增加(P<0.05)。不同时间段给予METH组的给药次数和有效鼻触次数均没有显著性差异,但是从8 d的给药次数来看,分别为8:00-8:30组(86.2±23.8)<10:00-10:30组(104.3±41.3)<11:30-12:00组(123.4±50.3)<16:00-16:30组(155.0±51.7)。从前4 d给药时间8:00-8:30改为后4 d给药时间11:30-12:00后,给药次数和有效鼻触次数明显增加(P<0.05);从前4 d给药时间11:30-12:00改为后4 d给药时间8:00-8:30后,给药次数和有效鼻触次数明显减少(P<0.05)。8组大鼠间无效鼻触次数没有显著差异。结论 10:00-17:00时间段进行训练有利于大鼠自身给药行为的形成。

Influence of different training time on formation of methamphetamine self-administration in rats

OBJECTIVE To investigate the methamphetamine(METH) administrered at the different time on the formation of METH self-administration in rats. METHODS The gualified rats were chosen for the experiment after 6 d under FR1 program. According to four periods of administration times with 8:00-8:30, 10:00-10:30, 11:30-12:00 and 16:00-16:30 and two administration factors with normal saline and METH 0.05 mg·kg^-1, the rats were separated into four groups and trained for 8 d. The parameters, self-administration times, and the number of active and inactive pokes were observed and analyzed with the SuperState Version 4.0 behavior control software. RESULTS Compared with the vehicle control group at the same training time, the self-administration times and active poke numbers in all of the four METH groups increased significantly (P<0.05). The self-administration times and active poke numbers in each METH group at different training time didn't increase significantly. The number of self-administration times was the smallest in 8:00-8:30 group (86.2±23.8), followed by 10:00-10:30 group (104.3±41.3), 11:30-12:00 group (123.4±50.3) and 16:00-16:30 group (155.0±51.7). The self-administration times and active poke numbers of the rats in METH group significantly increased when the initial training time (8:00-8:30) was changed to 11:30-12:00 in the last four days(P<0.05). And self-administration times and active poke numbers significantly decreased when the initial training time(11:30-12:00) was changed to 8:00-8:30 in the last four days(P<0.05). CONCLUSION The formation of METH self-administration in rats is easier when the training time is from 10:00 to 17:00.