骶髓后连合核接受盆内脏伤害性信息传入的形态学证明

为阐明投射至骶髓后连合核的盆内脏初级传入中是否含有传递伤害性信息成分，本研究综合运用特异性标记初级传入Ｃ纤维的ＢＳＩ－Ｂ４－ＨＲＰ跨节追踪技术，神经干局部涂抹Ｃ纤维毒素ＣａＰｓａｉｃｉｎ并结合ＳＰ免疫组化方法，研究了猫投射至骶髓后连合核的盆神经初级传入纤维中是否含有传递伤害性刺激的成分；同时观察了秋水仙素处理的骶２后根节内ＢＳＩ－Ｂ４标记的初级传入神经元与ＳＰ免疫阳性神经元的关系。结果如下：（１）向盆神经注入ＢＳＩ－Ｂ４－ＨＲＰ，骶１～３后根节内出现平均直径３４μｍ的标记细胞，后连合核内出现密集的标记终末，电镜下证明通过Ｌｉｓｓａｕｅｒ氏束进入脊髓内的标记纤维均为无髓纤维；（２）对盆神经进行局部Ｃａｐｓａｉｃｉｎ处理，引起后连合核内的ＳＰ免疫阳性纤维和终末明显减少；（３）骶２后根节内ＢＳＩ－Ｂ４－ＦＩＴＣ标记细胞有１７％同时呈ＳＰ免疫阳性；（４）骶２后根节内ＢＳＩ－Ｂ４－ＨＲＰ标记的盆内脏初级传人神经元的３９％同时呈ＳＰ免疫阳性。本研究结果在形态学上证实了骶髓后连合核接受盆腔内脏伤害性信息的传入，它可能是中继和整合盆内脏伤害性信息的低级中枢。

MORPHOLOGICAL EVIDENCE THAT THE DORSAL COMMISSURAL NUCLEUS OF THE SACRAL SPINAL CORD RECEIVES NOXIOUS AFFERENTS FROM PELVIC VISCERA

The dorsal cormmissural nucleus (DCN) of the sacral spinal cord receives both pelvic visceral primary afferents and somatic primary afferents, and the convergence of visceral and somatic inputs onto neurons in the DCN has been confirmedboth anatomically and electrop hysiologically. But it was unclear Whether the DCN receives no xious afferent inputs frompelvic viscera or not. Therefore, the aim of the present study was first to find out if the DCN receives C-fibre afferents fromthe pelvic viscera, by application of BSI-B4-HRP to pelvic nerve, and secondly to investigate whether the SP-like immunoreactive terminals in the DCN derive from the pelvic nerve, by administration of capsaicin to pelvic nerve. In addition, co-local-ization of BSI-B4 with SP-like immunoreactivity of dorsal root ganglionic cells was examined. (1) In the three cats, the diam-eters (mean±S.E. ) of the labeled cells in S2 dorsal root ganglion were 35. 5 ± 0.24, 33. 7±0.31 and 34.6± 0. 21 um.Those neurons which labeled by BSI--B4 appear to be a subpopulation of the small-diameter cells. In the dorsal horn, thecomponents of the DCN were densely by BSI-B4. Electron microscopic analysis of the sacral Lissauer's tract revealedthat BSI-B4 labeles a subpopulation of unmyelinated fibres, no myelinated fibres were labeled. (2) SP- like immunoreactivityWas markedly depleted in the region, including the DCN, of sacral spinal cord terminations of the pelvic nerve which treatedby capsaicin. (3) 17% of the BSI-B4-FITC-bound cells were SP-immunoreactive in S2 dorsal root ganglion. (4) 39% of thecells labeled by BSI-B4-HRP that was injected into pelvic nerve in S2 dorsal root ganglion were SP-immunoreactive.These results, together with our previous electrophysiological studies, indicat that DCN receives noxious afferent inputsfrom the pelvic viscera, that is, the DCN of the sacral spinal cord is a centre which relay and modulate the noxious information from the pelvic viscera.