黑质网状带GABAB受体对大鼠运动行为的影响

EFFECT OF GABAB RECEPTOR ACTIVATION IN RAT SUBSTANTIA NIGRA PARS RETICULATA ON THE RAT ROTATIONAL BEHAVIOR

目的观察黑质网状带GABAB受体激活对大鼠运动行为的影响。方法大鼠单侧黑质网状带埋置套管,恢复3 d后,于清醒大鼠核团分别微量注射生理盐水、GABAB受体激动剂巴氯芬(1 mmol/L)、GABAB受体阻断剂CGP55845A(1 mmol/L)、CGP55845A和巴氯芬的混合物0.2μL,观察其旋转行为的变化。结果单侧黑质网状带微量注射巴氯芬,大鼠立刻出现明显的对侧旋转行为,与盐水对照组比较,差异有统计学意义(u=0.00,P<0.01)。这种对侧旋转行为可以被CGP55845A所阻断,与单纯注射巴氯芬相比,差异有统计学意义(u=0.00,P<0.01);仅注射CGP55845A本身并不会产生明显的旋转行为(u=9.00,P>0.05)。结论黑质网状带GABAB受体激活可抑制其神经元兴奋性,从而解除基底神经核对丘脑及大脑皮质运动区的抑制效应,导致运动功能增强。

Objective To observe the effect of GABAB receptor activation in substantia nigra pars reticulata on the rat behavior. Methods A guide cannulus constructed from stainless steel was implanted into the substantia nigra pars reticulata. After three days of recovery, 0. 2μL of solutions containing GABAB receptor agonist baclofen, GABAB receptor antagonist CGP55845A, CGP55845A＋baclofen separately, or normal saline of same volume were microinjected into the substantia nigra pars reticulata in awake rats. Rotational behavior was observed within 30 min. Results Unilateral microinjection of baclofen （1 mmol/L） caused a robust contra-lateral rotation, the times of rotation were significantly higher than that of the control animals （u=0.00, P〈0.01）. The rotation could be prevented by co-microinjection of I mmol/L CGP56846A （u=0.00, P〈0.01 ）. Microinjection of 1 mol/L CGP55845A only did not cause any rotation （u= 9. 00,P〉0. 05）. Conclusion GABAB receptor activation inhibits the activity of neurons in substantia nigra pars reticulata, which in turn increases the movement output from thalamus and cortex.