Comparison of electroacupuncture and morphine-mediated analgesic patterns in a plantar incision-induced pain model

Yen Jing Zeng, Shih-Ying Tsai, Kuen Bao Chen, Sheng Feng Hsu, Julia Yi Ru Chen, Yeong Ray Wen

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Electroacupuncture (EA) is a complementary therapy to improve morphine analgesia for postoperative pain, but underlying mechanism is not well-known. Herein, we investigated EA-induced analgesic effect in a plantar incision (PI) model in male Sprague-Dawley rats. PI was performed at the left hind paw. EA of 4 Hz and high intensity or sham needling was conducted at right ST36 prior to PI and repeated for another 2 days. Behavioral responses to mechanical and thermal stimuli, spinal phospho-ERK, and Fos expression were all analyzed. In additional groups, naloxone and morphine were administered to elucidate involvement of opioid receptors and for comparison with EA. EA pretreatment significantly reduced post-PI tactile allodynia for over 1 day; repeated treatments maintained analgesic effect. Intraperitoneal naloxone could reverse EA analgesia. Low-dose subcutaneous morphine (1 mg/kg) had stronger inhibitory effect on PI-induced allodynia than EA for 1 h. However, analgesic tolerance appeared after repeated morphine injections. Both EA and morphine could equally inhibit PI-induced p-ERK and Fos inductions. We conclude that though EA and morphine attenuate postincision pain through opioid receptor activations, daily EA treatments result in analgesic accumulation whereas daily morphine injections develop analgesic tolerance. Discrepant pathways and mechanisms underlying two analgesic means may account for the results.

Original languageEnglish
Article number659343
JournalEvidence-based Complementary and Alternative Medicine
Volume2014
DOIs
Publication statusPublished - Sep 29 2014
Externally publishedYes

ASJC Scopus subject areas

  • Complementary and alternative medicine

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