[The effect of halothane anesthesia on dopamine release induced by apomorphine or haloperidol--an in vivo microdialysis study in rats striatum]

Brain microdialysis was used to study in vivo releases and changes in dopamine (DA) concentration induced by neuroleptics in the rat striatum during halothane anesthesia. Rats were implanted with a microdialysis probe into the right striatum and allowed to move freely. After acquiring steady state of DA and metabolites concentrations, apomorphine 50 micrograms.kg-1 or haloperidol 200 micrograms.kg-1 was administered intraperitoneally with or without 1.5% halothane anesthesia for 1 h. Halothane anesthesia showed no effect on the decrease of DA induced by apomorphine, but halothane antagonized the increase of DA induced by haloperidol. Administration of haloperidol produced an increase in metabolites of DA and it was unchanged by halothane. Malignant syndrome is a well known complication caused by interaction of neuroleptics and anesthesia. The results of the present investigation suggest that the mechanism of malignant syndrome might be associated with the dopaminergic activity.