豚鼠耳蜗血管交感神经支配的逆行追踪与免疫组化相结合的双标

目的:研究豚鼠耳蜗螺旋蜗轴动脉接受交感神经支配的具体来源情况及与该交感神经纤维调节功能相关的神经递质. 方法:在正常豚鼠单侧耳蜗螺旋蜗轴动脉局部滴加逆行追踪剂辣根过氧化物酶(HRP)或荧光金(FG),观察双侧交感颈上神经节、星状神经节内HRP或FG逆标神经元的分布;采用逆标与免疫组化相结合的双重标记方法观察追踪阳性神经元是否表达酪氨酸羟化酶(TH)、神经肽Y(NPY)、钙基因相关肽(CGRP)或P物质(SP). 结果:同侧颈上神经节内可见逆行追踪阳性神经元胞体,对侧颈上及双侧星状神经节内却未见阳性细胞;阳性神经元多同时呈TH, NPY阳性,但未见CGRP或SP双标的阳性神经元. 结论:豚鼠颈上神经节内存在TH及NPY阳性神经元支配同侧耳蜗血管,去甲肾上腺素和神经肽Y可能是交感神经节后纤维调节耳蜗血流的递质或调质.

Sympathetic nerve-innervated cochlear blood vessels in guinea pig: Retrograde tracing combined with immunohistochemical double-labeled technique

AIM: To investigate the detailed innervation patterns of the sympathetic nerve to the cochlear blood vessels and related neurotransmitters in the guinea pig. METHODS: The spiral modiolar artery(SMA) in guinea pig cochlea was exposed by microsurgery, then the fluorogold(FG) or horseradish peroxidase(HRP) was given around the SMA for retrograde tracing. The bilateral superior cervical ganglia(SCG) and stellate ganglia(STG) were observed to find retrogradely labeled neurons. The neurotransmitters of these sympathetic fibers around SMA were ascertained by using retrograde tracing combined with immunohistochemical double-labeled technique. RESULTS: Retrogradely labeled neurons with FG or HRP were found in the rostral half of the ipsilateral SCG. No labeled neurons were observed in the contralateral SCG and the bilateral STG. Most of HRP-labeled neurons in SCG were TH-IR positive and NPY-IR positive, while none of them were CGRP-or SP-positiue. CONCLUSION: The TH-IR positive and NPY-IR positive neurons in SCG send projections to the ipsilateral cochlear blood vessels. The norepinephrine and NPY may be used by sympathetic nerve to regulate cochlear blood flow.