Warenycia M W, McKenzie G M, Murphy M, Szerb J C
Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Neuropharmacology. 1987 Aug;26(8):1107-14. doi: 10.1016/0028-3908(87)90255-3.
Bilateral removal of the fronto-parietal cortex of the rat resulted in decreased spontaneous multiple-unit activity recorded in the striatum of freely-moving rats. Cortical ablations changed the neuronal response in the striatum to systemic administration of dexamphetamine (2.5 mg/kg i.p.) from excitation in control animals (88%) to inhibition in ablated animals (61%). Furthermore, catalepsy, induced by haloperidol, but not by morphine, was markedly attenuated after cortical ablation. These changes were accompanied by a 23% decrease in the specific binding of [3H]spiperone in the striatum. The binding of [3H]met-enkephalin was unaffected by the cortical lesions. Levels of glutamate in the striatum decreased from 8.88 +/- 0.5 mumols/g in control animals to 6.93 +/- 0.37 mumols/g after bilateral cortical ablation. On the other hand, cortical ablations did not alter the content of either the gamma-aminobutyric acid or glutamine of the striatum. It is concluded that the excitatory response, observed in striatal neurons in freely-moving animals, is dependent upon an intact cerebral cortex and requires intact cortico-striatal afferents. The results further suggest that neurons in the striatum are under the tonic influence of glutamate, released from cortico-striatal afferents. Lastly, some dopamine D2 binding sites in the striatum are located on cortico-striatal afferent terminals and blockade of these striatal D2 sites may be involved in the induction of catalepsy by neuroleptic drugs.
双侧切除大鼠额顶叶皮质会导致自由活动大鼠纹状体中记录到的自发多单位活动减少。皮质切除改变了纹状体神经元对腹腔注射右旋苯丙胺（2.5毫克/千克）的反应，在对照动物中为兴奋（88%），而在切除动物中变为抑制（61%）。此外，由氟哌啶醇而非吗啡诱导的僵住症在皮质切除后明显减轻。这些变化伴随着纹状体中[3H]司哌啶特异性结合减少23%。[3H]甲硫氨酸脑啡肽的结合不受皮质损伤影响。纹状体中谷氨酸水平从对照动物的8.88±0.5微摩尔/克降至双侧皮质切除后的6.93±0.37微摩尔/克。另一方面，皮质切除并未改变纹状体中γ-氨基丁酸或谷氨酰胺的含量。得出的结论是，在自由活动动物的纹状体神经元中观察到的兴奋性反应依赖于完整的大脑皮质，并且需要完整的皮质-纹状体传入纤维。结果进一步表明，纹状体中的神经元受到从皮质-纹状体传入纤维释放的谷氨酸的紧张性影响。最后，纹状体中的一些多巴胺D2结合位点位于皮质-纹状体传入终末，阻断这些纹状体D2位点可能与抗精神病药物诱导僵住症有关。
