降钙素基因相关肽在大鼠“合谷”穴区相关感觉和运动神经元中的表达

The Expression of Calcitonin Gene-related Peptide in the Sensory and Motor Neurons Associated with “Hegu”(LI 4) in the Rat

目的:综合运用神经示踪和荧光免疫组织化学技术揭示合谷穴区相关感觉和运动神经元的化学表达。方法:先将荧光素594结合霍乱毒素亚单位B(AF 594-CTB)分别注入4只大鼠"合谷"穴区确定与其相关神经元在脊神经节和脊髓中的分布,然后在对应的组织切片上用降钙素基因相关肽(CGRP)免疫染色方法显示所标记神经元的化学特征。结果:所有AF 594-CTB标记的神经元均出现在示踪剂注入侧的脊神经节和脊髓前角。所标记的感觉神经元以C 7脊神经节为中心分布在C 5-T 1的脊神经节中,其中73.5%表现为CGRP阳性;所标记的运动神经元以C 8节段为中心分布在C 6-T 1脊髓前角的后外侧部,全部表现为CGRP阳性。结论:CGRP广泛存在于支配合谷穴区的感觉和运动神经元中,提示针刺合谷穴可能会通过这些神经元对CGRP发挥调节作用。

Objective To investigate the chemical expression of the primary sensory and motor neurons associated with ＂Hegu＂ （LI 4） area by using neural tracing and fluorescent immunohistochemical techniques, Methods A total of 4 SD rats were used in the present study. After anesthesia, the rats received microinjection of 5 μL of Alexa Fluor 594 conjugated cholera toxin subunit B fAF 594-CTB） into the right ＂Hegu＂ （LI 4） area for observing the distribution of the related primary sensory neurons in dorsal root ganglia （DRGs） and motor neurons in the spinal cord （C 1- C 5）. Three days after the microinjection, the rats were anesthetized and transcardiacally perfused with 4 % paraformaldehyde, followed by routine section of the DRGs and spinal cord tissues. The labeled neurons were observed by light microscope and their chemical characteristics determined by calcitonin gene- related peptide （CGRP） fluorescent immunohistochemical method. Results All the AF 594-0TB labeled neurons in DRGs and spinal cord were located on the side of the tracer injection. The labeled sensory neurons distributed in DRGs of cervical （C） 5 to thoracic （T） 1 segments with a high concentration in C 7 DRG in which 73.5% sensory neurons were shown to be CGRP-positive. The labeled motor neurons were found to be in the dorsolateral region of the spinal anterior horns from C 6 to T 1 segments, with a high concentration at C 8 in which 100% motor neurons were shown to be OGRP-positive. Conclusion Acupoint LI 4 is inner- vated by sensory neurons from DRGs of O 5 - T 1 and motor neurons from anterior horns of the same segmental spinal cord in rats, Among them, 73.5% of the sensory neurons and 100% of the motor neurons are CGRP-positive, suggesting an involvement of CGRP in acupuncture stimulation-LI 4 induced therapeutic effects.