大鼠尾壳核的GABA能传递在条件性行为调控中的作用

本工作采用了行为和脑内注射相结合的方法研究了大鼠尾壳核的 GABA 能传递在条件性行为调控中的作用。在分辨学习的基础上训练大鼠完成条件性回避任务,以比较药物对分辨学习和条件性回避的不同效应。实验结果表明,于大鼠双侧尾壳核内分别注入 γ-氨基丁酸(GABA)(每侧100μg/μl)和 GABA 受体激动剂蝇蕈醇(Muscimol)(每侧0.1μg/μl)后可暂时抑制条件性回避反应的出现,但分辨学习无明显影响。作为对照,于尾壳核内注入等量的生理盐水则既不影响条件性回避反应,也不影响分辨学习。在条件性回避反应被 Muscimol抑制后于尾壳核内再注入 GABA 受体阻断剂印防己毒素(PTX)(每侧0.1μg/μl)则可拮抗Muscimol 的行为抑制效应,即条件反应的出现率可恢复到或接近注射前水平。实验结果表明,大鼠尾壳核的 GABA 能传递在条件性行为调控中的重要作用。

THE ROLE OF GABA-ERGIC TRANSMISSION OF CAUDATE-PUTAMEN NUCLEUS(CPN)IN THE CONTROL OF CONDITIONED BEHAVIOR IN RATS

Using the method of bilateral injection of GABA (100 micrograms/microliters) and muscimol (0.1 micrograms/microliters) into the caudate-putamen nucleus (CPN) we have studied the role of GABA-ergic transmission of CPN in the control of conditioned behavior. In order to compare the effects of GABA and muscimol on two behavioral paradigms, rats of either sex weighing 160-180 g were trained to perform discrimination learning and conditioned avoidance response. A tone (1 kHz, 80 dB) was used as a conditioned stimulus. After bilateral injections of GABA and muscimol into the trained rats' CPN respectively, the conditioned avoidance response was inhibited temporarily, whereas the discrimination learning remained almost unchanged. In addition, the inhibitory effect of muscimol on the conditioned avoidance response was attenuated or even abolished by following bilateral intra-CPN injection of picrotoxin (0.1 micrograms/microliters for each side). As a control, the same volume of saline was injected into CPN bilaterally, and it showed that there was no change of both the conditioned avoidance response and the discrimination learning. The results show that the GABA-ergic transmission of CPN does play a role in the control of avoidance conditioning in rats, and thus support the suggestion that GABA-ergic transmission of the caudate-globus pallidus plays an important role in the control of conditioned behavior.