鸡脊髓后角Ⅰ、Ⅱ层内大神经元的免疫细胞化学研究

The Immunocytochemical Study of Large Dorsal Horn Neurons in the Laminae Ⅰ and Ⅱ of the Chicken Spinal Cord

本研究采用心脏灌流法固定鸡标本 ,切取鸡脊髓颈膨大部分 ,利用免疫细胞化学法 ( PAP法 ) ,在光镜下观察了后角大神经元 ,其周围有大量 SP样免疫反应终扣。大神经元的胞体主要分布在 层、 层外侧区和 层内 ;树突伸向 层、 层外侧区以及 层的深部。电镜下观察 ,在 层内 ,大神经元的树突与突触小球的 P物质阳性中心终末形成突触。这一发现提示 ,大神经元直接接受来自初级感觉传入终末的信息。结合以前的研究推测

The chickens were fixed by perfusion through the heart in this study. The cervical enlargement of the spinal cord was removed. The immunocytochemical method (PAP) was performed. Large neurons outlined with nuerons substance P (SP) like immunoreactive (LI) boutons were detected immunocytochemically in the dorsal horn of the chicken spinal cord at the light microscopic level. Cell bodies of the large neurons were mostly localized in the lamina Ⅰ and the region lateral to the lamina Ⅰ. Some of the cell bodies were also located in the lamina Ⅱ. Their dendrites extended in the lamina Ⅰ, in the region lateral to the lamina Ⅰ, and deeply in the lamina Ⅱ. In the lamina Ⅱ, dendrites of these neurons formed synapses with SP containing central terminals in synaptic glomeruli known to originate from primary afferents. The findings suggest that these large neurons receive nociceptive information directly from primary afferents. In the light of previous investigations, these neurons are considered to the be pain transmitting long ascending tract neurons.