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