Tomie A, Cunha C, Mosakowski E M, Quartarolo N M, Pohorecky L A, Benjamin D
Department of Psychology, Rutgers University, New Brunswick, NJ 08903, USA.
Psychopharmacology (Berl). 1998 Sep;139(1-2):154-9. doi: 10.1007/s002130050700.
Approach responses, consummatory behaviors, and directed motor responses maintained by food reward resemble autoshaping CRs and are increased by lower doses of ethanol. This study evaluated the effects of presession i.p. injections of ethanol doses (0.00, 0.25, 0.50, 0.70. or 1.00 g/kg) on the acquisition of lever-press autoshaping CR performance in groups of male Long-Evans hooded rats. Paired groups received 15 daily sessions of Pavlovian autoshaping procedures, wherein the insertion of a retractable lever for 5 s (CS) was followed by the response-independent presentation of food (US). Ethanol facilitated lever-press autoshaping CR acquisition, as revealed by dose-related increases in the number of trials on which CRs were performed. The form of the dose-effect curve was inverted U-shaped with maximal responding induced during sessions 1-5 by the 0.70 g/kg ethanol dose. A similar dose-effect curve was observed during sessions 11-15, revealing that the effects of ethanol on autoshaping CR performance were relatively stable. A pseudoconditioning control group injected presession with 0.50 g/kg ethanol received training wherein the food US was presented randomly with respect to the lever CS. Few lever-presses were performed by the Random 0.50 group, indicating that ethanol's effects on autoshaping CR acquisition and maintenance observed in the Paired 0.50 group were not due to its psychomotor activating effects. A non-injection control group performed more autoshaping CRs than did the control group injected presession with saline, indicating that daily presession i.p. injections per se suppress autoshaping CR performance. Results reveal that low doses of ethanol enhance Pavlovian conditioning of directed motor and consummatory-like responding maintained by food reward. Implications for autoshaping accounts of impulsivity and drug abuse are considered.
由食物奖励维持的趋近反应、 consummatory 行为和定向运动反应类似于自动塑造条件反应，并会因较低剂量的乙醇而增强。本研究评估了在雄性 Long-Evans 有帽大鼠组中，在实验前腹腔注射乙醇剂量（0.00、0.25、0.50、0.70 或 1.00 g/kg）对杠杆按压自动塑造条件反应性能习得的影响。配对组接受了 15 天的巴甫洛夫自动塑造程序，其中可伸缩杠杆插入 5 秒（条件刺激）后，会出现与反应无关的食物呈现（非条件刺激）。乙醇促进了杠杆按压自动塑造条件反应的习得，这表现为进行条件反应的试验次数与剂量相关的增加。剂量效应曲线的形式为倒 U 形，在第 1 - 5 次实验中，0.70 g/kg 的乙醇剂量诱导了最大反应。在第 11 - 15 次实验中观察到了类似的剂量效应曲线，表明乙醇对自动塑造条件反应性能的影响相对稳定。一个假条件控制组在实验前注射 0.50 g/kg 的乙醇，接受的训练是食物非条件刺激相对于杠杆条件刺激随机呈现。随机 0.50 组几乎没有进行杠杆按压，这表明在配对 0.50 组中观察到的乙醇对自动塑造条件反应习得和维持的影响并非由于其精神运动激活作用。一个非注射对照组比在实验前注射生理盐水的对照组进行了更多的自动塑造条件反应，这表明每天实验前腹腔注射本身会抑制自动塑造条件反应性能。结果表明，低剂量的乙醇增强了由食物奖励维持的定向运动和类似 consummatory 反应的巴甫洛夫条件作用。还考虑了对冲动性和药物滥用的自动塑造解释的影响。
