[The effect of halothane or sevoflurane anesthesia on the extracellular concentration of dopamine and its metabolites examined by in vivo microdialysis techniques].
BACKGROUND
Volatile anesthetics induce changes in the extracellular concentration of dopamine (DA) metabolites in the rat striatum and their metabolism might be modified in different manners by different anesthetics. Although, we have studied DA metabolism during anesthesia using in vivo microdialysis techniques, time dimensional changes were not assessed concerning the difference between anesthetics. In the current investigation, the rats were anesthetized with halothane or sevoflurane, which has different blood solubility, and investigated the effect of anesthetics and time-related development on DA metabolism.


METHODS
The rats were implanted with a microdialysis probe in the striatum and perfusate was introduced to HPLC every 20 min. Anesthesia was induced with halothane or sevoflurane for 20 or 60 min, and methamphetamine 2 mg x kg(-1) was administered during or after inhalation.


RESULTS
Both anesthetic agents increased the concentration of DA metabolites, and dose and time dependency was more obvious with sevoflurane than with halothane. The increase of metabolites was prolonged after halothane anesthesia (20 min), but the effect of methamphetamine administered immediately after anesthesia on DA release was not enhanced by halothane anesthesia. Sevoflurane, not halothane anesthesia, antagonized methamphetamine-induced decrease of metabolites.


CONCLUSIONS
Not only the difference of blood solubility between halothane and sevoflurane and anesthetic effect of time dependency, but also another pharmacological property affects DA metabolism, including the change in the activity of dopamine transporter during inhalation of anesthetics.
Adachi
Yushi
Y
Intensive Care Unit of University Hospital, Hamamatsu University School of Medicine, Hamamatsu.
Higuchi
Hideyuki
H
Watanabe
Kazuhiko
K
Kazama
Tomiei
T
Doi
Matsuyuki
M
Sato
Shigehito
S
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D006221:Halothane / Q000494:pharmacology*; D008694:Methamphetamine / Q000494:pharmacology; D008738:Methyl Ethers / Q000494:pharmacology*; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D008694:Methamphetamine; D006221:Halothane; D004298:Dopamine