Objectives To compare the neural pathways associated with the tissues located at different traditional acupuncture points in the rat forehead and face using the cholera toxin B subunit (CTB) neural tracing technique.
Methods After injection of CTB into the tissues at GB14, ST2 and ST6 in the rat, the neural labelling associated with each acupuncture point was revealed by fluorescent immunohistochemistry of the nervous system, including the trigeminal ganglion (TRG), cervical dorsal root ganglia (DRG), spinal cord and brain.
Results The CTB labelling included sensory neurons and their transganglionic axonal terminals, as well as motor neurons. The labelled sensory neurons associated with GB14, ST2 and ST6 were distributed in both the TRG and cervical DRG, and their centrally projected axons terminated in an orderly fashion at their corresponding targets in the spinal trigeminal nucleus and cervical spinal dorsal horn. In addition, labelled motor neurons were observed in the facial motor nucleus, trigeminal motor nucleus and cervical spinal ventral horn, in which facial motor neurons projected to the tissues located at all three acupuncture points. Trigeminal motor neurons innervated both ST2 and ST6, while spinal motor neurons only correlated with ST6.
Conclusions These results indicate that the tissues located at each of these three traditional acupuncture points in the rat forehead and face has its own sensory and motor connection with the nervous system in a region-specific pattern through distinct neural pathways. Understanding the neuroanatomical characteristics of acupuncture points from the peripheral nervous system to the central nervous system should help inform acupuncture point selection according to the demands of the clinical situation.
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JW and JC contributed equally.
Contributors The work presented here was carried out in collaboration between all authors. JW and JC contributed equally. JW, JC, CS, DX, ZZ, and HW carried out the experiments and analysed the data. JC and WB designed the study. JW and WB wrote the paper. All authors read and approved the final version of the manuscript accepted for publication.
Funding This study was funded by the National Natural Science Foundation of China (ref. 81373557, 81403327, 81774211 and 81774432), and the Self-Selected Research Program from China Academy of Chinese Medical Sciences (ref. ZZ16010 and ZZ201711001).
Competing interests None declared.
Patient consent Not required.
Ethics approval This study was approved by the ethics committee at the Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
Provenance and peer review Not commissioned; externally peer reviewed.
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