Effects of repeated sevoflurane and rivastigmine on spatial learning and memory in weanling rats

Abstract

It has been reported that repeated sevoflurane exposure induces cognitive impairment. On the other hand, there is evidence that rivastigmine can attenuate or antagonize the cognitive dysfunctions caused by anesthetic agents. The aims of this study were to determine the effect of repeated sevoflurane exposure on spatial learning and memory (SLM) in weanling rats and to assess whether rivastigmine provides protection against the neurotoxic effects of sevoflurane at this early developmental stage. Methods: Thirty-two weanling rats were randomly divided into four equal groups: sevoflurane (S: 2% sevoflurane for 2 hours), sevoflurane + rivastigmine (SR: 2% sevoflurane and 2 mg/kg rivastigmine), rivastigmine (R: 2 mg/kg), and control (C: 100% oxygen for 2 hours). Rats were treated four times over 10 days. Four days after the last treatment, the rats were subjected to a Morris water maze test protocol to examine SLM. Results: The escape latencies of all groups gradually decreased day by day during the training trials performed to evaluate spatial learning (ρ<0.05). Group R showed more improvement than other groups as the rats in this group learned significantly more slowly on the first and second days of the training trials but reached the same levels as Group S and Group SR on the third and last days (ρ<0.05). In the probe trial to evaluate spatial memory, no significant difference was found among the groups for time spent in the 'platform' quadrant (ρ>0.05). Conclusion: Sevoflurane negatively affects learning in weanling rat pups but has no detrimental effect on spatial memory. On the other hand, it can be claimed that sevoflurane offsets the memory-sparing effects of rivastigmine.