Effect of dexmedetomidine pretreatment on contents of glutamic acid and γ-aminobutyric acid dur-ing focal cerebral ischemia-reperfusion in rats

Abstract

Objective To evaluate the effect of dexmedetomidine pretreatment on contents of glutamic acid and γ-aminobutyric acid during focal cerebral ischemia-reperfusion (I/R) in rats. Methods Thirty-six clean-grade healthy male Wistar rats, aged 10 months, weighing 250-300 g, were divided into 3 groups using a random number table method: sham operation group (group S), I/R group, and dexmedetomidine group (group D). Focal cerebral I/R was induced by occlusion of the left middle cerebral artery for 30 min followed by reperfusion in anesthetized rats.The left middle cerebral artery was only isolated but not occluded in group S. Sterile normal saline 1 ml was intraperitoneally injected, and 30 min later the model of focal cerebral I/R was established in group I/R.Rats were sacrificed at the end of reperfusion, and brains were removed for determination of contents of glutamic acid and γ-aminobutyric acid in brain tissues and for examination of ultrastructure (with an electron microscope). Results Compared with group S, the content of glutamic acid was significantly increased, and the content of γ-aminobutyric acid was decreased in I/R and D groups (P<0.05). Compared with group I/R, the content of glutamic acid was significantly decreased, and the content of γ-aminobutyric acid was increased in group D (P<0.05). The damage to the ultrastructure of brain tissues was significantly attenuated in group D when compared with group I/R. Conclusion Dexmedetomidine pretreatment can reduce focal cerebral I/R injury through decreasing the content of glutamic acid and increasing the content of γ-aminobutyric acid in rats. Key words: Dexmedetomidine; Brain; Reperfusion injury; Glutamic acid; gamma-Aminobutyric acid