大鼠腰骶髓P物质受体阳性神经元向外侧臂旁核投射

本研究应用四甲基罗达明 (TMR)逆行追踪结合 P物质受体 (SPR)免疫荧光组织化学染色技术 ,观察了大鼠腰骶髓后连合核 (DCN)和中间带外侧核 (IML)内的 SPR阳性神经元向外侧臂旁核 (L PB)的投射。将 TMR注入一侧 L PB后 ,可在腰骶(L6 ～ S2 )节段观察到大量红色的 TMR逆标神经元 ,这些 TMR逆标神经元主要集中于 DCN和 IML内 ,多为中型 (直径 2 0～ 5μm)梭形、三角形或多极形 ;SPR阳性神经元也主要分布于 DCN和 IML内 ,并以 IML 居多 ;部分 TMR逆标神经元同时呈 SPR阳性。上述结果提示腰骶髓 DCN及 IML内的 SPR阳性神经元可能接受由 SP介导的盆腔内脏伤害性信息并将之向 LPB传递。

PROJECTION OF SUBSTANCE P RECEPTOR IMMUNOPOSITIVE NEURONS IN THE LUMBOSACRAL SPINAL CORD TO THE LATERAL PARABRACHIAL NUCLEUS IN THE RAT

Employing tetramethyl rhodamine (TMR) retrograde tracing combined with immunofluorescence histochemical staining for substance P receptor (SPR),we examined whether SPR-like immunoreactive neurons in the lumbosacral dorsal commissural nucleus (DCN) and intermediolateral nucleus (IML) sent projection fibers to the lateral parabrachial nucleus (LPB) in the rat. After injecting TMR into the unilateral LPB, TMR retrogradely labeled neurons were observed mainly in L6-S2 segments ipsilateral to the TMR injection, especially in the DCN and IML,and the vast majority of them were medium (diameter ranged from 20 to 35 μm) fusiform, triangular and multipolar neurons. In addition to laminaeⅠ and Ⅲ, SPR-like immunoreactive neurons were also observed in the DCN and IML, especially in the IML. Some of the TMR retrogradely labeled neurons also exhibited SPR-like immunoreactivities. The results suggest that SPR-like immunoreactive neurons in the DCN and IML of the lumbosacral spinal cord might be innervated by substance P containing primary afferent fibers, which convey visceral nociceptive information of the pelvic organs, and transmit it to the LPB.