Mechanism of dexmedetomidine-induced reduction of acute visceral pain in rats: relationship be-tween α2 adrenergic receptors and expression of Nav1. 8 in dorsal root ganglion neurons
10.3760/cma.j.issn.0254-1416.2019.03.028
- VernacularTitle:右美托咪定减轻大鼠急性内脏痛的机制:α2肾上腺素能受体与背根神经节神经元Nav1.8表达的关系
- Author:
Fengxiang GU
1
;
Yufang LENG
;
Jipeng LYU
;
Chenmei PENG
;
Guangru ZHANG
;
Jun FAN
Author Information
1. 兰州大学第一医院麻醉科 730000
- Keywords:
Dexmedetomidine;
Visceral pain;
Receptors;
adrenergic;
alpha-2;
Ganglia;
spinal;
NAV1.8 voltage-gated sodium channel
- From:
Chinese Journal of Anesthesiology
2019;39(3):361-364
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the relationship betweenα2 adrenergic receptors and expression of Nav1. 8 in dorsal root ganglion (DRG) neurons, and to illuminate the mechanism of dexmedetomidine-induced reduction of acute visceral pain in rats. Methods Thirty-two clean-grade healthy adult male Spra-gue-Dawley rats, aged 6-8 weeks, weighing 180-220 g, were divided into 4 groups ( n=8 each) using a random number table method: control group ( group C ) , acute visceral pain group ( group VP ) , dexmedetomidine group (group D), and dexmedetomidine plus atipamezole group (group DA). In VP, D and DA groups, 10-3 mmol∕L capsaicin 1. 3 ml was injected into the rectum at a dose of 10-3 mmol∕L to establish the acute visceral pain model, while the equal volume of normal saline was given instead in group C. Atipamezole 1 mg∕kg was subcutaneously injected through the back of the neck at 20 min before establishing the model in group DA. Dexmedetomidine 10μg∕kg was injected through the tail vein at 15 min before establishing the model in D and DA groups, while the equal volume of normal saline was given instead at the correspording time points in C and VP groups. The visceral pain behavior score was recorded at 1 h after establishing the model. The animals were then sacrificed, and DRGs of the lumbar segment (L3-6) were removed for determination of the number of Nav1. 8 positive DRG neurons (by immunohisto-chemistry) and expression of Nav1. 8 mRNA (by quantitative real-time polymerase chain reaction). Results Compared with group C, the visceral behavior scores and the number of Nav 1. 8 positive DRG neurons were significantly increased, and the expression of Nav 1. 8 mRNA was up-regulated in VP, D and DA groups (P<0. 05). Compared with group VP, the visceral behavior score and the number of Nav1. 8 positive DRG neurons were significantly decreased, and the expression of Nav 1. 8 mRNA was down-regulated in D and DA groups (P<0. 05). Compared with group D, the visceral behavior scores and the number of Nav1. 8 positive DRG neurons were significantly increased, and the expression of Nav1. 8 mRNA was up-regulated in group DA ( P<0. 05) . Conclusion The mechanism by which dexmedetomidine reduces acute visceral pain is related to activatingα2 adrenergic receptors and to down-regulating the expression of Nav1. 8 in DRG neu-rons of rats.
