[Halothane anesthesia decreases the level of interstitial striatal dopamine of awake freely moving rats in an in vivo microdialysis study].

We investigated the effect of halothane on the level of interstitial dopamine of in vivo awake, free moving rats brain striatum using microdialysis techniques. Rats were implanted a microdialysis probe to right striatum of the brain and administered 1.5% of halothane (approximately 1.2 MAC) for 1 or 2 hours, and dialysates from the probe were determined every 20 minutes. Halothane anesthesia reduced the amount of dopamine derived from dialysate, and after discontinuation of halothane and at emergence from anesthesia, the level of dopamine was increased. The levels of metabolites of dopamine during anesthesia were increased lineally in a time dependent manner. We hypothesized that halothane might increase the rate of re-uptake of dopamine at nerve endings and decreased level of interstitial dopamine is compensated by dopamine releases during anesthesia.