The Journal of Korean Medicine (대한한의학회지)

The Society of Korean Medicine (대한한의학회)
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Activation of spinal Serotonergic Receptor Contributes to Electroacupuncture Analgesia in Rat with Chronic Pain

만성통증이 유발된 흰쥐에서 관찰된 침진통효과의 세로토닌성 기전

  • Park Dong-Suk (Department of Acupuncture and Moxibustion, College of Oriental Medicine, Kyunghee University) ;
  • Shin Hong-Kee (Department of Physiology, College of Medicine, Hanyang University) ;
  • Lee Kyung-Hee (Department of Physiology, College of Medicine, Hanyang University)
  • 박동석 (경희대학교 한의과대학 침구학교실) ;
  • 신홍기 (한양대학교 의과대학 생리학교실) ;
  • 이경희 (한양대학교 의과대학 생리학교실)
  • Published : 2005.09.01
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Abstract

Objectives : Electroacupuncture (EA)-induced analgesia has been known to be mediated through the activation of opioid, noradrenergic and serotonergic receptors. However, little study on serotonergic mechanism has been performed in an animal model of chronic pain. The present study was designed to elucidate the type of serotonergic receptors responsible for EA analgesia in the chronic pain model. Methods : In rats with complete Freund's: adjuvant-induced inflammation and spinal nerve injury, spinal wide dynamic range (WDR) cell responses to graded electrical stimulation of afferent C fiber were recorded before and after spinal application of selective 5-hydroxytryptamine (5-HT) receptor antagonists. EA stimulation (2Hz, 0.5msec, 3mA) was applied to the contralateral Zusanli point for 30 min. Results : In both models of chronic pain, WDR cell responses were greatly inhibited after EA stimulation. EA-induced inhibition of WDR celt responses was significantly attenuated by spinal application of non-selective 5-HT receptor antagonist, dihydroergocristine Of 5-HT receptor antagonists tested, 5-HT1A (WAY 100635) and 5-HT2 (LY53857) receptor antagonists strongly reduced an ability of EA stimulation to inhibit WDR cell responses. However, 5-HT1B (GR55562) and 5-HT3 (LY278584) receptor antagonists also had weak but significant blocking action on EA-induced inhibitory effect on chronic pain. Conclusions : Dorsal hem cell responses, afferent C fiber stimulation, chronic pain, electroacupuncture, serotonergic receptors.

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