Effect of preemptive analgesia and noxious stimulation during anesthesia on dopamine metabolism in the prefrontal cortex

Abstract

Using the microdialysis method, we evaluated the effect on the prefrontal cortex of noxious stimulation during anesthesia, and the role of 6-amino-3 hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate receptors. We also examined the effect of preemptive analgesia (PA) on the dopaminergic neuron system in the prefrontal cortex. Electric stimulation of the dorsum pedis decreased dopamine (DA) by 20% (p<0.05), while electric stimulation after addition of 6-cyano-7-nitroquinoxaline-2.3-dione, an AMPA/kainate receptor antagonist, to the dialyzing solution futher decreased DA. These findings suggest that noxious stimulation during general anesthesia, unlike during arousal, decreases DA in the prefrontal cortex, and that AMPA/kainate receptors inhibit this decrease. In addition, although noxious stimulation during anesthesia decreased DA in the prefrontal cortex, epidural anesthesia inhibited this decrease.