阿扑吗啡注射对大鼠视觉线索辨别学习和逆反学习的影响

The effect of apomorphine on visual discrimination learning and reversal learning in rats

目的利用阿扑吗啡和旋转T迷宫装置，观察阿扑吗啡对大鼠视觉线索辨别学习和逆反学习的影响。方法首先通过食物奖励与灯光线索的结合，训练所有动物的视觉线索辨别学习任务。在此期间，分别在每次学习前30min或学习后立即腹腔注射阿扑吗啡（0.5mg／kg）。当动物达到所规定的学习标准后，开始逆反学习的训练。结果与生理盐水注射组相比[学习次数分别为（168．00±16．97）次和（163．20±20．08）次]，视觉线索辨别学习前、后的阿扑吗啡注射都能干扰视觉线索辨别学习任务的获得[学习次数分别为（259．20±26．29）次和（264．00±16．97）次]；而只有在视觉线索辨别学习后立即注射阿扑吗啡，才能干扰逆反学习任务的获得[学习次数为（451．20±39．44）次，而相应的生理盐水组为（360．00±29．39）次]。结论对于视觉线索辨别学习，阿扑吗啡注射干扰了学习的获得和保持；对于随后的逆反学习，视觉线索辨别学习后的阿扑吗啡注射通过抑制原有学习策略的消退过程，从而干扰逆反学习任务的获得。

Objective Using apomorphine, a potent dopamine receptor agonist and rotating T-maze, the effect of apomorphine on the visual discrimination learning and reversal learning in rats was investigated. Methods All rats were trained in a visual discrimination task （food reward and light stimulus） in rotating T-maze. After reaching the acquisition criterion, rats were trained in a reversal task （food reward and without light stimulus） in the same maze. During the period of visual discrimination task, apomorphine was administrated either 30 minutes prior to learning or after learning immediately. Results The results showed that apomorphine, which was given either 30 minutes prior to visual discrimination learning or after learning, could impair the acquisition of discrimination learning（ 259.20 ± 26.29 and 264.00 ± 16.97, compared to 168.00 ± 16.97 and 163.20 ± 20.08 ） and apomorphine, which was given only after visual discrimination learning, could impair the acquisition of reversal learning （451.20 ± 39.44 compared to 360.00 ± 29.39 ）. Conclusion The results showed that apomorphine, which was given either 30 minutes prior to visual discrimination learning or after learning, could impair the acqui- sition of discrimination learning and apomorphine, which was given only after visual discrimination learning, could impair the acquisition of reversal learning.