猫内脏大神经一级传入纤维在脊髓灰质和薄束核中的分布

THE DISTRIBUTION OF PRIMARY AFFERENT FIBERS FROM THE GREATER SPLANCHNIC NERVE TO THE SPINAL GRAY MATTER AND NUCLEUS GRACILIS IN THE CAT

本文共用猫14只,取1~1.5mg HRP溶于7~10μl蒸馏水中,注入一侧的腹腔神经节或内脏大神经中,采用TMB成色法,观察跨神经节传递的一级内脏传人纤维在中枢神经系的分布。标记的一级内脏感觉纤维经后根进入脊髓后,绝大多数先行于背外侧束(或Lissauer束)中,少数进入后索上行。自背外侧束间断地发出内、外侧投射纤维,包绕着后角的内、外侧缘。外侧投射纤维在数量上比内侧的多,止于Ⅰ、Ⅴ、Ⅶ层和中央管周围。进入中间外侧核的纤维,再沿颅尾方向分开纵行,与交感节前细胞的纵向树突紧密平行排列。内侧投射纤维主要止于中央管周围区域。行于后索的纤维,止于闩平面以下薄束核的腹外侧部。

The central distribution of visceral primary afferent fibers from greater splanchnic nerve of the cat have been studied.Horseradish peroxidase(HRP)dissolved in distilled water was injected into the coeliac ganglion or greater splanchnic nerve unilaterally.The HRP was taken up by afferent fibers and transported across the spinal ganglia and then anterogradely as far as central terminals in the spinal cord and medulla.The HRP reaction-product within the central processes of the primary sensory neurons was detected ipsilaterally in the Lissauer’s tract,dorsal funiculus and spinal gray matter.After entering the spinal cord via the spinal dorsal roots,the great majority of labeled fibers(viz.the central processes of primary sensory neurons)were found to run longitudinally within the zone of Lissauer,and only sparse fibers to ascend in the dorsal funiculus.The medial projection fibers(MPF)and lateral projection fibers(LPF)arose periodically from the labeled fiber bundle in the Lissauer’s tract to form a thin shell surrounding both the medial and lateral sides of the dorsal horn.The terminal areas of the more prominent LPF were found at laminae I,V,VII and the region surrounding the central canal,whereas the MPF ended at the medial part of lamina V and lamina X.Some smaller fiber bundles from LPF were seen to enter the cell clusters of the intermediolateral nucleus,where these fibers divided rostrocaudally and ran parallel with the longitudinal dendritic branches of the intermediolateral cells.The few labeled fibers located at the dorsal funiculus were traced to the lower medulla and the distinct terminal area of them was situated in the ventrolateral part of the nucleus gracilis at the level below the obex.