TRPV1 is a Responding Channel for Acupuncture Manipulation in Mice Peripheral and Central Nerve System

Abstract

Background/Aims: Acupuncture involves inserting a fine needle into a specific point, often called an acupoint, thereby initiating a therapeutic effect accompanied by phenomena such as soreness, heaviness, fullness, and numbness. Acupoints are characterized as points located in deep tissues with abundant sensory nerve terminals, which suggests that there is a strong relationship between acupoints and peripheral sensory afferents. In this study, we determined whether manual acupuncture (MA) or different frequencies of electroacupuncture (EA) share similar mechanisms for activating excitatory neurotransmission. Methods: We performed MA or EA at acupoint ST36 and we also used western blot and immunostaining techniques to determine neural changes at the peripheral dorsal root ganglion (DRG), spinal cord (SC), and somatosensory cortex (SSC) levels. Results: Our results show that either MA or EA at the ST36 acupoint significantly increased components of the TRPV1-related signaling pathway, such as pPKA, pPI3K, pPKC-pERK, and pAKT (but not pp38 or pJNK) at the peripheral DRG and central SC-SSC levels. Furthermore, excitatory phosphorylated N-methyl-D-aspartate receptor (pNMDA) and pCaMKIIα (but not pNR2B, pCaMKIIδ, or pCaMKIIγ) also increased. These molecules could not increase in the DRG and SC-SSC of TRPV1–/–mice. Conclusion: Our data demonstrates that both MA and EA can activate excitatory signals in either peripheral or central levels. We also define that TRPV1 is crucial for an acupuncture effect and then initiate excitatory pNR1-pCaMKII pathway, at peripheral DRG and central SC-SSC level. We suggest that the TRPV1 signaling pathway is highly correlated to Acupuncture effect that implies the real clinical significance.