Neuronal Correlation Between Acupoint BL 23 and Kidney in the Rat
ZHANG Zhiyun, WANG Hui, XU Dongsheng, BAI Wanzhu*
(Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China)
Abstract: Objective: To research the distribution of the neurons associated with kidney and acupoint “Shenshu” (BL 23) area in the rat and explore the neuroanatomical basis of acupoint-visceral correlation.
Methods Normal male SD rats were used as present experimental subjects. Under the respiratory anesthesia, AF488-CTB (green) was injected subcutaneously into the left side of BL 23 area, at the same time, AF594-CTB (red) was injected into the same side of kidney that was exposed by local surgery. Both injections were performed in the same rat. Three days after injection, the rats were transcardially perfused with 4% paraformaldehyde in 0.1 M phosphate buffer (PB), and dorsal root ganglions (DRG), spinal cord, and sympathetic chain were dissected out and stored in 25% sucrose PB at 4°C for sample making.The neuronal labeling with AF488/594-CTB can be directly observed under a fluorescent microscope or a laser scanning confocal microscope. Results The sensory neurons associated with kidney and acupoint BL 23 distributed from thoracic (T) 10 to lumbar (L) 2 and T11 to L3 DRG respectively, and some of them were labeled with both AF488/594-CTB and coexisted in T13 DRG. For the sympathetic innervation, the postganglionic sympathetic neurons associated with both kidney and acupoint BL 23 were found in the sympathetic chain at the same lumbar segments and labeled with AF488/594-CTB separately . In addition, the motor neurons associated with acupoint BL 23 area were mainly detected in the spinal ventral horn of cord at thoracic segments and also a few at cervical segments. Conclusions These results reveal that sensory neurons associated with both kidney and acupoint BL 23 area can be the basis of correlation between them in the sensory nervous system. In addition, the postganglionic sympathetic neurons associated with kidneyand acupoint BL 23 area locate adjacently in the same sympathetic ganglion, further demonstrating sympathetic connection between them. Present study suggests that stimulating signals from acupoint BL23 area can be transported to the kidney through both sensory and sympathetic pathway simultaneously.
Keywords: acupuncture, shenshu (BL 23), kidney, neural tracing technique, neuron