Efforts of sevoflurane and scopolamine on muscarinic acetylcholine receptors in hippocampus in gerontal rats

Abstract

Objective To investigate the effects of sevoflurane and scopolamine on muscarinic acetylcholine receptors in hippocampus in gerontal rata.Methods Forty-eight male SD rats aged 18 months weighing 560-600 g were randomly divided into 3 groups(n=16 each):group Ⅰcontrol(C);group Ⅱ inhaled 3%sevoflurane for 2 h(Sevo);group Ⅲ received intraperitoneal scopolamine 0.8 mg/kg.Y-maze was used to test the abihty of learning and memow at 1 and 3 d after drug administration in 8 animals from each group.The animals were decapitated immediately after Y-maze test at 1 and 3 day after drug administration.The hippocampus was removed for determination of the relative levels of expression of M1 and M2 acetylcholine receptor(mAChR M1,M2)mRNA(by RT-PCR)and the expression of mAChR MI and M2(by immuno-histochemistry).Results The ability to learn and remenlber and the expression of M1 and M2 AChR and AChR mRNA were significantly decreased at 1 d after sevoflurane inhalation(in group Ⅱ)and scopolamine IP administration(in group m)aS compared with control group and returned to control level at 3 d.Conclusion The ability to learn and remember cfln be reduced for a short period of time after sevoflurane inhalation and IP scopolamine throgh down-regulation of Ml and M2 mAChR in the brain. Key words: Anesthetics,inhalation; Scopolamine; Cognition disorders; Hippocampus; Aged; Receptor,muacarinic M1; Receptor,muscarinic M2