Effect of dexmedetomidine on norepinephrine release in midbrain periaqueductal gray in a rat model of incisional pain
10.3760/cma.j.issn.0254-1416.2011.03.007
- VernacularTitle:右美托咪啶对切口痛大鼠中脑导水管去甲肾上腺素释放的影响
- Author:
Yanru ZENG
;
Shouzhang SHE
;
Lixin XU
;
Xuebing XU
- Publication Type:Journal Article
- Keywords:
Dexmedetomidine;
Pain;
Mesencephalon;
Cerebral aqueduct;
Norepinephrine
- From:Chinese Journal of Anesthesiology
2011;31(3):292-295
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effect of dexmedetomidine on norepinephrine(NE)release in midbrain periaqueductal gray(PAG)in a rat model of incisional pain.Methods Twenty-four male Wistar rats in which microdialvsis catheter was successfully placed in the ventrolateral region of PAG without complications were randomly divided into 4 groups(n=6 each):group control(group C);group incisional pain(group IP);group dexmetomidine(group D)and group dexmedetomidine+yohimbine(group DY).Incisional pain was induced by an incision made into the plantar surface of left hindpaw in IP,D,DY groups.Dexmedetomidine 30 μg/kg and dexmedetomidine 30 μg/kg+yohimbine 0.5 mg/kg were given intraperitoneally at 15 min before plantar incision in group D and group DY respectively.Mechanical paw withdrawal threshold(MWT)to von Frey filament stimulation was measured at 30 min before(baseline)and 1,2,3,4 h after operation in C,IP,D groups,and at 30 min before(baseline),and 1 h after operation in group DY.Dialysate samples were collected at 30 min before(baseline)and at evcry 30 min after operation for 4 h via cerebral microdialysis catheter for determination of the NE concentration in C,IP,D groups,and at 30 min before(baseline),30,60 min after operation in group DY.Results Incisional pain significantly decreased MWT and increased the NE concentration in dialysate in group IP.Dexmedetomidine premedication significantly inhibited mechanical hyperalgesia and attenuated incisional pain-induced increase in the NE concentration in dialysate in group D.Yohimbine counteracted effects of dexmedetomidine.Conclusion Dexmedetomidine has analgesic effect though inhibition of NE release from PAG.
