东莨菪碱对程序诱导的大鼠烦渴行为的影响

Effects of scopolamine on schedule-induced polydipsia in rats

目的 观察东莨菪碱对大鼠程序诱导的烦渴行为 (schedule inducedpolydipsia ,SIP)建立和维持的影响。 方法 在每天 3小时实验期内 ,通过程序性供应食物 (固定时间 6 0s)诱导限食大鼠建立SIP行为。结果 连续 7天实验前 15min东莨菪碱 (0 .35 ,1.0mg/kg ,i.p .)处理减弱大鼠已建立稳定的SIP(P <0 .0 5 ,n =6 ) ,停药后 7天 ,这种抑制作用在进行第 2次药物处理时被减弱。从SIP训练第一天开始连续 7天实验前 15min东莨菪碱 (0 .35mg/kg ,i.p .)处理 ,大鼠实验期间饮水量与对照组相比没有显著差别 ,但停药后SIP行明显减弱 ,而再次给予东莨菪碱处理时SIP行为被显著加强 (P <0 .0 5 ,n =6 )。结论 胆碱能神经系统参与SIP行为的调节 。

Objective To observe the effects of scopolamine on initiation and maintenance of schedule-induced polydipsia (SIP) in rats.Methods Schedule induced-polydipsia (overdrinking) was induced when food-deprived rats were subjected to a fixed time (60s) feeding schedule for 3 hours daily.Results Established SIP were significantly attenuated by 15min pre-session treatment with scopolamine (0.35, 1.0mg/ kg, i.p.) for 7 consecutive days(P<0.05, n=6), after 7 days withdrawal of scopolamine, the attenuating effect of scopolamine on SIP was decreased. When scopolamine (0.35 mg/ kg, i.p.) were given from the first SIP training session for 7 consecutive days, no statistically significant effect was found on water intake during test sessions comparing with control, however, SIP were significantly lowered after withdrawal of scopolamine for 7 days, and enhanced by scopolamine re-treatment(P<0.05, n=6). Conclusion Results suggested that cholinergic muscarinic system underlie the mediation of schedule-induced polydipsia. Different effects of scopolamine on initiation and maintenance of SIP implied that these two processes might involve different mechanisms.