Effects of memantin on recovery cognitive function and pain in aged rats after propofol anesthesia

Postoperative cognitive dysfunction is a frequent complication after anesthesia and propofol is an intravenous anesthetic agent that has been proved to cause cognitive dysfunction. There are many risk factors such as age for postoperative cognitive dysfunction. Memantine has beneficial effects on memory deficits and learning process. Besides, it is neuroprotective effects and can be used in treatment of chronic pain syndromes. This study was designed to determine the effects of memantine on recovery, cognitive functions and pain in aged rats undergoing general anesthesia with propofol.30 aged Wistar rats were divided into 5 groups randomly. For Group K 0,9% NaCl (1 ml i.p.) was administered at 21.day, for Group P propofol (100 mg/kg i.p.) was administered at 21.day, for Group OMP propofol (100 mg/kg, i.p.) was administered after 20 days of treatment with 20 mg/kg/day oral memantine, for Group OM memantine (20 mg/kg/day oral) was administered for 20 days, for Group IPMP propofol (100 mg/kg) was administered after 30 minutes memantine (1 mg/kg i.p. in 1 ml SF) were applied. Recovery was evaluated by tail pinch test, cognitive functions were evaluated by RAM, S100ß and NSE and pain was evaluated by hot-plate. In this study recovery times were shorter in Group OMP and Group IPMP when compared to Group P (p=0.016). Cognitive functions of rats in Group OMP and Group IPMP were better than Group P for the first value of recovery (p<0,05). Hot-plate test values in all groups, except group K were longer at all time points when compared to control values (p<0,05). NSE and S100 levels were higher in Group P when compared to Group K. The levels of S100ß and NSE levels were comparable in Groups K, OMP and IPMP. This study showed that memantine has beneficial effects on negative effects of propofol on recovery, cognitive functions and pain.