摘要
将 CB-HRP 注入鸡泄殖腔壁内,通过逆行和跨节追踪证明:1、被标记的泄殖腔初级传入神经元胞休位于双侧 T_4—S_9脊神经节和迷走神经结状节内。脊神经节内的标记细胞集中于 S_4—S_7和 T_6—L_1。分别以 S_5和 L_1为高峰,L_4—S_2为少标记区.荐段和胸腰段标记细胞数的比系1.6∶1,结状节内的标记细胞数较前二者少.脊神经节内的标记细胞以小型的为主,结状节内的标记细胞则以大型者居多。单侧注射例大约有39%的标记细胞出现于对侧脊神经节中。2、脊髓横断面观,被标记的初级传入神经元中枢突呈束状经背根外侧部进入S_3—S_8髓节的背外侧束,而后分成内外两部。外侧纤维束较粗大,沿背角Ⅰ—Ⅴ层外侧缘走行,内侧纤维束较细小,向内侧穿经 Clarke 氏柱,二者于中介核处汇合,共同终止于荐部副交感节前柱。单侧注射例,对侧的标记纤维束较注射侧疏淡。水平面观,背角外侧有被标记的纵向纤维束,以 S_5为中心向前后各伸延2～3个节段。在 T_7—L_2可见有纤细的纤维束沿背角外侧缘走行。
CB-HRP was injected into the wall of Cloaca in the chicken and traced with retrograde and transganglionic transport.The results were as follows.1.The labeled primary afferent cells from the cloaca were located bilaterally in the spinal ganglia T_4—S_9 and nodose ganglia The labeled cells in the spinal ganglia were concentrated in S_4—S_7 (mainly S_5)and T_6—L_1(mainly L_1),and there was a less-labeled- area in L_4—S_2.The ratio of the labeled ceils in the sacral ganglia to th those in the thoracolumbar was about 1.6:1,and the ones in the nodose ganglia were fewer.The labeled cells in the spinal ganglia were mainly small ones,while those in the nodose were principally large.About 39% of the labeled ceils were found in the contralate- ral spinalganglia even though the HRP was injected into one side of the cloaca wall only.In the transverse plane,entering the S_3—S_8spi hal cord,the labeled central processes of primary afferent neurons of the cloaca first appeared in the dorsolateral tract,and then divided into medial and lateral parts.The lateral fiber bundle was thicker and larger,and run ventromedially along the lateral border of lays I-V in the dorsal horn.The medial one was thiner and smaller,and crossed the Clarke's column in the middle part of the dorsal horn.The two parts joined in the intercalated nucleus and terminated in the colu- tuna preganglionica saeralis.In the horizontal section,the labeled fibers formed a wider longitudinal tract(namely Lissauer's tract) which extended two to three segments rostrocaudally,centering on the S_5.Additionally,fine fiber bundle was also observed in the lateral border of dorsal horn in the T-7—L_2.
