Redgrave P, Marrow L P, Dean P
Department of Psychology, University of Sheffield, U.K.
Neuroscience. 1992;46(2):391-406. doi: 10.1016/0306-4522(92)90060-f.
Lesion evidence suggests that the superior colliculus is essential for mediating the anticonvulsant properties of nigral suppression in the electroshock model of epilepsy. However, our companion paper [Redgrave et al. (1991) Neuroscience 46, 379-390] established that the region of dorsal midbrain where bicuculline was most effective in suppressing tonic hindlimb extension did not correspond well with the known distribution of nigrotectal terminals. The purpose of the present anatomical study was, therefore, to investigate in more detail ventral midbrain connections to the dorsal midbrain anticonvulsant zone in rat. Small injections (10-20 nl) of a 1% solution of wheatgerm agglutinin conjugated with horseradish peroxidase were made specifically into the region of dorsal midbrain where bicuculline was maximally effective. Numerous retrogradely labelled cells were found in substantia nigra pars lateralis and adjacent peripeduncular area but not in substantia nigra pars reticulata. Retrogradely labelled cells were also located in ventral zona incerta. When wheatgerm agglutinin-horseradish peroxidase injections were made into lateral substantia nigra, a region of anterogradely transported reaction product characteristic of nerve terminals was observed in the caudolateral deep layers and underlying reticular tissue; this area corresponded well to the dorsal midbrain anticonvulsant zone. These data suggest that, in the electroshock model of epilepsy, direct connections between substantia nigra pars lateralis and adjacent peripeduncular area and the dorsal midbrain anticonvulsant zone could be critical for mediating the anticonvulsant properties previously attributed to substantia nigra pars reticulata. During the course of this study, anterograde projections from substantia nigra pars lateralis and adjacent peripeduncular area to both superficial and intermediate layers of the ipsilateral superior colliculus were noted. Additional experiments using retrograde transport of the fluorescent tracer Fast Blue confirmed these projections.
损伤证据表明，在癫痫电休克模型中，上丘对于介导黑质抑制的抗惊厥特性至关重要。然而，我们的配套论文[雷德格雷夫等人（1991年），《神经科学》46卷，379 - 390页]证实，在中脑背侧区域，荷包牡丹碱在抑制强直性后肢伸展方面最有效，但这与已知的黑质 - 顶盖终末分布并不完全相符。因此，本解剖学研究的目的是更详细地研究大鼠中脑腹侧与中脑背侧抗惊厥区的连接。将1%与辣根过氧化物酶偶联的麦胚凝集素溶液进行小剂量注射（10 - 20纳升），专门注入中脑背侧荷包牡丹碱作用最有效的区域。在黑质外侧部和邻近的脚周区发现了大量逆行标记细胞，但在黑质网状部未发现。逆行标记细胞也位于腹侧未定带。当将麦胚凝集素 - 辣根过氧化物酶注入黑质外侧时，在尾外侧深层和下方的网状组织中观察到了神经终末特有的顺行运输反应产物区域；该区域与中脑背侧抗惊厥区非常吻合。这些数据表明，在癫痫电休克模型中，黑质外侧部和邻近脚周区与中脑背侧抗惊厥区之间的直接连接对于介导先前归因于黑质网状部的抗惊厥特性可能至关重要。在本研究过程中，注意到了黑质外侧部和邻近脚周区向同侧上丘浅层和中间层的顺行投射。使用荧光示踪剂快蓝逆行运输的额外实验证实了这些投射。
