家兔脊髓固有束的起始细胞和终支的分布——HRP法研究

THE SITE OF THE ORIGIN AND TERMINATION OF THE PROPRIOSPINAL TRACT IN THE RABBIT——A HRP STUDY

将HRP分别注入家兔脊髓的C_(6,7)、L_(5,6)和T_(5~7),C注射者观察L_(5)和T_(5),L注射者观察C_(5)和T_(5),T注射者观察C_(5)和L_(5)的标记细胞和顺行标记终支。标记细胞大量且恒定地存在于Ⅶ(包括胸髓的侧角)、Ⅷ层;其次为Ⅴ层和Ⅹ区;Ⅰ层的标记细胞多见于C、L,于T基本未见;Ⅳ、Ⅵ层的标记细胞不恒定且数量少;Ⅸ层在T可见少量,于L仅见个别,在C则未见到;Ⅱ、Ⅲ层于所有各例均未见到标记细胞。标记终支分布范围较广,几乎见于灰质各层。以Ⅹ区、Ⅶ层(包括胸髓的侧角)和Ⅷ层较为密集;L注射例在C_(5)腹角的腹外侧可见到明显的丛状终支,而于C注射例在L_(5)则未见到此特殊结构。还见到一些标记终支重叠在标记细胞上或紧挨其附近,也见到标记终支存在于未标记的运动神经元旁。根据形态学结果提出以下几点看法:1.胸髓Ⅶ区外侧分(侧角)出现标记细胞和终支,提示脊髓节段间联系不仅与躯体运动有关,而且也和内脏活动有关。2.Ⅹ区标记细胞恒定,标记终支也较密集,提示该区在脊髓节段间的联系方面起着一定的作用。3.腰膨大发出长的上升束,直接到达颈膨大腹角的腹外侧份,起着对运动神经元直接调节的作用。4.标记细胞旁有标记终支说明脊髓节段间有着反馈联系。

HRP was injected into C_(6),C_(7),L_(5),L_(6)or T_(5~7)spinal gray.The retrogradely labeled cells and anterogradly labeled terminal arborizations were traced in L_(5)and T_(5)in cervical injection cases,C_(5)and T_(5)in lumbar cases,and C_(5),L_(5)in thoracic cases.Large amount of labeled cell were consistently found in laminaeⅦ(including the lateral horn of the thoracic cord)andⅧ,next numerous in laminaⅤandⅩregion.LaminaⅠwas found labeled in the cervical and lumbar cord,but virtually not found in the thoracic cord.Labeled cells were few and inconsistent in laminaeⅣandⅥ.A few labeled laminaⅨcells could be found in the thoracic cord,only occasionally in the lumbar cord,but could not be found in the cervical cord.LaminaeⅡandⅢwere free from labeled cells in all cases.The labeled terminal arborizations were more widespread and could be found in practically every lamina,being densest in regionⅩ,laminaeⅦ(including the lateral horn of the thoracic cord)andⅧ.In lumbar injection cases a prominent plexus of labeled terminal arborization could be seen in the ventrolateral part of the C_(5)ventral horn.Corresponding plexus was not found in the lumbar cord in cervical injection cases.Some labeled terminal arborizations were found in close approximation to or overlapping with labeled cells or unlabeled motor neurons.These results imply that:(1)The occurance of labeled cells and labeled terminal arborizations in the lateral part of laminaⅦ(lateral horn)suggests that intersegmental connection is related to visceral activities as well as somatic ones.(2)Labeled cells were consistently found in regionⅩwhich was also the area of dense labeling of terminal arborization,suggesting that this region plays a remarkable role in intersegmental connection.(3)Long ascending bundle connects the lumbar enlargement with the ventrolateral part of the motor neurons directly.(4)The close approximation of labeled terminal arborization and labeled cells signifies direct intersegmental feedback circuit.