[The effect of normobaric oxygen inhalation and halothane anesthesia on the level of interstitial striatal dopamine of rats using in vivo microdialysis study].

We investigated the effect of normobaric oxygen inhalation on the level of interstitial dopamine and its metabolites in in vivo brain striatum of awake, free moving rats using microdialysis techniques. Rats were implanted a microdialysis probe to the right striatum of the brain and administered pure oxygen for 1 hour, and dialysates from the probe were examined every 20 minutes by HPLC. Normobaric oxygen inhalation reduced the amount of dopamine derived from the dialysate and increased that of metabolites. Halothane anesthesia with oxygen showed a slight effect on the changes induced by oxygen inhalation, whereas halothane significantly increased the level of dopamine metabolites. Pretreatment with glutathione failed to prevent increase of dopamine metabolites. We hypothesized that oxygen inhalation and halothane anesthesia might increase the level of dopamine metabolites in different mechanisms, and the changes induced by oxygen inhalation might not be the result of simple oxidative stress in rat striatum.