Neuroanatomical interconnection of the complementary acupoints in the rat hindlimb

Objective:The innervations in Yinlingquan(阴陵泉SP9)and Yanglingquan(阳陵泉GB34)were investigated to explore the neuroanatomical interconnection of the complementary acupoints in the rat hindlimb.Methods:A dual neural tracing technique was used,six male Sprague-Dawley rats were included in experiment.Under anesthesia with isoflurane,cholera toxin subunit B conjugated with Alexa Fluor 488 and 594(CTB-AF488/594)were separately injected into SP9 and GB34 in the same rat.Three days later,the neural labeling was examined in the dorsal root ganglion(DRG),spinal cord,and sympathetic chain at lumbar(L)spinal segments under a laser scanning confocal microscope.Results:All neural labeling were present on the ipsilateral side of tracer injection,including sensory,motor and sympathetic postganglionic neurons.The sensory neurons associated with SP9 and GB34 were distributed in the DRG from L2 to L6 and concentrated in L3-L4 and L4-L5 respectively,while most of the double labeled sensory neurons were presented in L4.On the other hand,the labeled motor neurons for SP9 and GB34 were observed in the dorsolateral part of spinal ventral horn at L2-L4 and L3-L5 respectively,and some of them were double labeled at L4.In addition,the sympathetic postganglionic neurons related to SP9 and GB34 were found in the lumbar sympathetic chain respectively.Conclusion:The similarities of the sensory,motor,and sympathetic innervation of SP9 and GB34 in the rat provide the neuroanatomical evidence to understand the synergetic effect that arise from the stimulation at the complementary acupoints.