豚鼠耳蜗核SP阳性神经元向下丘的投射-HRP逆行追踪与免疫组化双标

目的 研究豚鼠耳蜗核P物质（SP）免疫反应阳性产物的分布特点及SP标记神经元向下丘投射方式。方法 采用辣根过氧化物酶（HRP）逆行追踪及免疫组织化学技术。结果 SP免疫反应（SP－IR）阳性的纤维和终末主要分布在耳蜗背侧核，而SP－IR阳性神经元主要分布在耳蜗腹侧核，在腹侧核尚可见SP阳性终末包绕SP阳性胸体形成环形结构，一侧下丘中央核注入HRP后，对侧耳蜗核HRP标记细胞分布于耳蜗前腹核及背侧核，耳蜗后腹核呈阴性反应。同侧耳蜗后腹核HRP标记神经元数量也较少，在对侧耳蜗前腹核，HRP－SP双标神经元约占标记细胞的44％，SP单标细胞占标记细胞的50％，HRP单标细胞占6％。耳蜗背侧核内侧也可见少量的双标细胞。结论 SP是耳蜗核上行投射神经元的递质或调质。

Projection of substance P positive neurons from cochlear neucleus to inferior colliculus: Retrograde tracing of HRP and immunohistochemical double-labeled technique

AIM To study the distribution characteristics of substance P (SP) immunoreactive (SP IR) positive neurons in cochlear nucleus and projection pattern of labeled neurons and SP HRP double labeled neurons from cochlear nucleus toinferior colliculus (IC). METHODS Immunohistochemistry and horseradish peroxidase (HRP) retrograde tracing technique were used in this study. RESULTS SP IR positive fibers and endings were distributed mainly in dorsal cochlear nucleus (DCN). But SP IR positive neurons mainly in ventral cochlear nucleus (VCN). The circular structure of SP positive terminals around the SP positive neurons also was seen in VCN. When HRP was injected into the central nucleus of IC, HRP labeled neurons were distributed mainly in anteroventral cochlear nucleus (AVCN) and DCN of contralateral cochlear nucleus, but posteroventral cochlear nucleus(PVCN) was negative. The number of HRP labelled neurons in PVCN of ipsilateral was few. In contralateral AVCN HRP SP double labeled neurons were 44%, SP labeled neurons were 50% and HRP labeled neurons were 6%. CONCLUSION SP may be one of neurotransmitter or modulator of auditory ascending projection.