Analgesic effects of transcutaneous auricular vagus nerve stimulation on partial sciatic nerve ligation-induced neuropathic pain in mice via serotonergic pathways.
Hyunjin Shin, Seunghwan Choi, Geehoon Chung, Sun Kwang Kim
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引用次数: 0
Abstract
Current treatments for neuropathic pain often provide limited relief and are associated with significant side effects. Transcutaneous auricular vagus nerve stimulation (taVNS) shows promise as a non-pharmacological analgesic approach; however, its optimal therapeutic configuration and underlying brain mechanisms remain incompletely understood. This study investigated the analgesic effects of taVNS on neuropathic pain in a mouse model induced by partial sciatic nerve ligation (PSL), exploring mechanisms and optimizing configurations. PSL-induced neuropathic pain in mice, characterized by mechanical allodynia, was significantly alleviated by taVNS. The most robust analgesic effects were observed with multiple bilateral taVNS sessions, administered once daily for three consecutive days, with effects persisting for at least 48 h post-stimulation. Immunohistochemical analysis of c-Fos expression revealed that taVNS increased neural activity in the dorsal raphe nucleus (DRN), a key source of serotonin, while simultaneously reducing activity in the central amygdala (CeA), a region critical for pain processing and affective responses. Further experiments demonstrated that the analgesic effects of taVNS were abolished by systemic administration of p-chlorophenylalanine, an inhibitor of serotonin synthesis. These findings underscore the critical role of serotonin signaling in mediating taVNS-induced analgesia for neuropathic pain. The study also highlights the importance of stimulation parameters, identifying a multiple bilateral configuration as particularly effective. Our results suggest that taVNS, potentially acting via the DRN-serotonergic system to modulate limbic structures like the CeA, holds significant potential as a non-pharmacological therapeutic option for managing neuropathic pain.
期刊介绍:
Molecular Brain is an open access, peer-reviewed journal that considers manuscripts on all aspects of studies on the nervous system at the molecular, cellular, and systems level providing a forum for scientists to communicate their findings.
Molecular brain research is a rapidly expanding research field in which integrative approaches at the genetic, molecular, cellular and synaptic levels yield key information about the physiological and pathological brain. These studies involve the use of a wide range of modern techniques in molecular biology, genomics, proteomics, imaging and electrophysiology.