title: Possible involvement of histamine, dopamine, and noradrenalin in the periaqueductal gray in electroacupuncture pain relief.
abstract: Acupuncture and electroacupuncture are used in pain relief; however, the mechanism underlying the analgesic effect of acupuncture is unclear. Several lines of evidence propose that the periaqueductal gray (PAG), which is one of the regions that contributes to the endogenous pain inhibitory system, is involved in the analgesic effect of acupuncture, and the region receives several neural projections such as histamine and noradrenalin and contains the dopamine cell bodies. The current study examined the effects of electroacupuncture at Zusanli (ST36) and Shangjuxu (ST37) acupoints, which are used for clinical pain control, on the release of neurotransmitters in the PAG in rats. Histamine and dopamine release was increased after pain stimulus, while the changes were completely abolished by electroacupuncture. Pain stimulus had no effect on noradrenalin release, but electroacupuncture increased its release. These findings indicate that acupuncture at Zusanli and Shangjuxu exerts an antinociceptive effect via the activation of neurons in the PAG and that the histaminergic, dopaminergic, and noradrenalinergic systems in the PAG are related to electroacupuncture-induced pain relief.
authors.affiliation: Department of Medical Science and Technology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Murotani
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishizuka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakazawa
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wang
authors.forename: Kazu
authors.initials: K
authors.lastname: Mori
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sasaki
authors.forename: Torao
authors.initials: T
authors.lastname: Ishida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamatodani
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism; D015671:Electroacupuncture; D005557:Formaldehyde; D006632:Histamine / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D010146:Pain / Q000139:chemically induced / Q000378:metabolism*; D059408:Pain Management; D010147:Pain Measurement; D010487:Periaqueductal Gray / Q000378:metabolism*; D011108:Polymers; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D018377:Neurotransmitter Agents; D011108:Polymers; D005557:Formaldehyde; D006632:Histamine; D004298:Dopamine; D009638:Norepinephrine; C003043:paraform