title: Extrasegmental analgesia of heterotopic electroacupuncture stimulation on visceral pain rats.
abstract: Acupuncture has been applied in the clinic to treat visceral pain for a long time. However, the underlying mechanism still remains unknown. In the present study, extrasegmental analgesia of electroacupuncture (EA) at orofacial acupoints on visceral pain rats was investigated. The results revealed that nociceptive EA stimulation applied at heterotopic acupoints or nonacupoints to activate A(δ) and/or C fibers induced c-fos expression in the paratrigeminal nucleus (PTN) and significantly inhibited acetic acid-induced abdominal contractions and c-fos expression in the nucleus of the solitary tract (NTS). However, non-nociceptive EA or non-EA stimulation applied at heterotopic acupoints was totally ineffective. After infraorbital nerves transaction or pretreated by capsaicin, the EA analgesia was dramatically inhibited. Snake venom pretreatment had no influence on this analgesia. Consequently, heterotopic EA stimulation trigger the pain-inhibiting effect of diffuse noxious inhibitory controls (DNIC), in which PTN-NTS secondary neural pathway may be involved and small-diameter (A(δ) and/or C) fibers are crucial.
authors.affiliation: Guangzhou University of Traditional Chinese Medicine, 12 Jichang Road, Guangzhou 510006, PR China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
authors.forename: Wenbin
authors.initials: W
authors.lastname: Fu
authors.forename: Wei
authors.initials: W
authors.lastname: Yi
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Xu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liao
authors.forename: Xinran
authors.initials: X
authors.lastname: Li
authors.forename: Jiesi
authors.initials: J
authors.lastname: Chen
authors.forename: Xuefang
authors.initials: X
authors.lastname: Liu
authors.forename: Nenggui
authors.initials: N
authors.lastname: Xu
mesh_terms: D019342:Acetic Acid / Q000009:adverse effects; D015669:Acupuncture Points; D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000698:Analgesia / Q000379:methods*; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation; D009412:Nerve Fibers / Q000502:physiology; D010146:Pain / Q000139:chemically induced; D059408:Pain Management; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012910:Snake Venoms / Q000494:pharmacology; D017552:Solitary Nucleus / Q000378:metabolism; D014278:Trigeminal Nuclei / Q000378:metabolism; D014781:Viscera / Q000294:innervation*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D012910:Snake Venoms; D019342:Acetic Acid; D002211:Capsaicin