Hernández-López S, Góngora-Alfaro J L, Martínez-Fong D, Rosales M G, Aceves J
Departamento de Fisiología, Biofisica y Neurociencias, Centro de Investigación y Estudios Avanzados del I.P.N., México, D.F.
Neuroscience. 1994 Sep;62(2):441-7. doi: 10.1016/0306-4522(94)90378-6.
Turning in circles is among the behaviors elicited by unilateral cholinergic stimulation of the substantia nigra. Recent studies have shown that microinjection of cholinergic agonists into the substantia nigra pars compacta increases dopamine release and turnover in the striatum of anesthetized rats [Hernández-López et al. (1992) Brain. Res. 598, 114-120; Blaha and Winn (1993) J. Neurosci, 13, 1035-1044]. In this study, the relationship between circling behavior and striatal dopamine release following cholinergic stimulation of the substantia nigra pars compacta neurons was assessed by brain microdialysis in awake rats. The results indicate that cholinergic stimulation of the substantia nigra pars compacta with the mixed nicotinic-muscarinic cholinergic agonist carbachol modulates striatal dopamine release, and this effect is accompanied by circling behavior and stereotypies. Microinjection of carbachol (109 nmol) in the caudal portions of the substantia nigra pars compacta induced contralateral circling associated with an increase of dopamine release in neostriatum. On the contrary, ipsilateral circling and reduction of striatal dopamine release was elicited when the same dose of the drug was applied in the rostral portions of the substantia nigra pars compacta. The above findings are in accordance with recent electrophysiological studies suggesting the existence of sub-populations of nigrostriatal dopaminergic neurons, and indicate that the substantia nigra pars compacta is functionally compartmentalized. We conclude that the cholinergic input to the substantia nigra pars compacta could modulate the motor behavior through regulating the firing rate of nigrostriatal dopaminergic neurons and dopamine release in the neostriatum.
转圈行为是黑质单侧胆碱能刺激引发的行为之一。最近的研究表明，向麻醉大鼠的黑质致密部微量注射胆碱能激动剂会增加纹状体中多巴胺的释放和周转[埃尔南德斯 - 洛佩斯等人（1992年），《脑研究》598卷，第114 - 120页；布拉哈和温（1993年），《神经科学杂志》13卷，第1035 - 1044页]。在本研究中，通过对清醒大鼠进行脑微透析评估了黑质致密部神经元胆碱能刺激后转圈行为与纹状体多巴胺释放之间的关系。结果表明，用烟碱 - 毒蕈碱混合型胆碱能激动剂卡巴胆碱对黑质致密部进行胆碱能刺激可调节纹状体多巴胺释放，且这种效应伴随着转圈行为和刻板动作。在黑质致密部尾部微量注射卡巴胆碱（109纳摩尔）会诱发对侧转圈，同时新纹状体中多巴胺释放增加。相反，当在黑质致密部头部应用相同剂量的药物时，则会引发同侧转圈和纹状体多巴胺释放减少。上述发现与最近的电生理研究结果一致，提示存在黑质纹状体多巴胺能神经元亚群，并表明黑质致密部在功能上是分区的。我们得出结论，黑质致密部的胆碱能输入可能通过调节黑质纹状体多巴胺能神经元的放电频率和新纹状体中多巴胺的释放来调节运动行为。
