Possible involvement of histamine, dopamine, and noradrenalin in the periaqueductal gray in electroacupuncture pain relief.
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.
Murotani
Tomotaka
T
Department of Medical Science and Technology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Ishizuka
Tomoko
T
Nakazawa
Hiroyuki
H
Wang
Xiaoming
X
Mori
Kazu
K
Sasaki
Kazuro
K
Ishida
Torao
T
Yamatodani
Atsushi
A
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
D018377:Neurotransmitter Agents; D011108:Polymers; D005557:Formaldehyde; D006632:Histamine; D004298:Dopamine; D009638:Norepinephrine; C003043:paraform