The effects of isoflurane and 2-amino-5-phosphonovalerate, a NMDA receptor antagonist, on the cerebral cortex glutamate content / 中华麻醉学杂志

ABSTRACT

Objective To study the changes in cerebral cortex glutamate (G) content induced by isoflurane inhalation alone or combined with 2-amino-5-phosphonovalerate (AP5),a NMDA receptor competitive antagonist.Methods Six adult male SD rats were anesthetized with isoflurane. Dialysis probe (internal diameter=0.05mm) which was connected to a micro-infusion pump filled with artifical cerebrospinal fluid(ACSF) was inserted into cerebral cortex. The dialysate was collected for determination of G concentration. After the baseline MAC for isoflurane was measured, the study was carried out in 4 groups based on the concentration of isoflurane inhalation group Ⅰ1%; group Ⅱ1MAC; group Ⅲ2% and group Ⅳ the effect of AP5 on isoflurane MAC value. In group Ⅳ AP5 was continuously infused at a rate of 100 ?g?kg -1?h -1 via the vein in the tail and the MAC for isoflurane was measured again. G concentration of dialysate was measured and EEG and SEP were monitored in every group.Results G concentration of cerebral cortex dialysate was decreasing with increasing concentration of isoflurane from group Ⅰ to group Ⅲ. Concentration of isoflurane was negatively correlated with cerebral G content (r=-0.839,P