Changes in expression of hippocampal α7nAChR, AChE and ChAT after sevoflurane anesthesia in neonatal rats

Objective To evaluate the changes in the expression of hippocampal α7 nicotinic acetylcholine receptor (α7nAChR), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) after sevoflurane anesthesia in neonatal rats. Methods Seventy-two healthy Sprague-Dawley rats of both sexes, aged 7 days, weighing 25-40 g, were divided into 3 groups (n=24 each) using a random number table method: control group (group C), air and oxygen group (group A/O) and sevoflurane group (group S). Rats were exposed to carrier gas (air 1 L/min plus oxygen 1 L/min) for 2 h in group A/O.Rats were exposed to 3.4% sevoflurane in carrier gas for 2 h in group S. Eight rats in each group were selected at 2 h, 1 week and 4 weeks after the end of inhalation, and sacrificed, brains were removed and hippocampal tissues were obtained for determination of α7nAChR, AChE and ChAT protein and mRNA by Western blot and real-time polymerase chain reaction, respectively. Results Compared with group A/O, the expression of α7nAChR mRNA was significantly down-regulated at each time point after the end of inhalation, and the expression of TnAChR was down-regulated at 2 h after the end of inhalation and up-regulated at 1 week after the end of inhalation, the expression of AChE mRNA was up-regulated at 2 h after the end of inhalation and down-regulated at 4 weeks after the end of inhalation, the expression of AChE was down-regulated at 4 weeks after the end of inhalation, the expression of ChAT mRNA was up-regulated at 2 h after the end of inhalation, and the expression of ChAT was down-regulated at each time point after the end of inhalation in group S (P<0.05). Conclusion The expression of hippocampal α7nAChR is down-regulated at first and then up-regulated after sevoflurane anesthesia, the expression of ChAT and AchE in the later period is down-regulated, the tendency of protein expression mentioned above is different from that of its mRNA expression, suggesting that sevoflurane may affect the protein expression through other pathways. Key words: Infant, newborn; Anesthetics, inhalation; Receptors, cholinergic; Acetylcholinesterase; Choline O-acetyltransferase