[The effect of isoflurane anesthesia on dopamine release in rat striatum with pretreatment of imipramine].
BACKGROUND
Isoflurane anesthesia has been shown to have a possibility of inducing a biphasic effect on dopamine release in rat striatum. The current study investigated the effect of isoflurane on the extracellular concentration of dopamine in the rat striatum pretreated by a classical antidepressant, imipramine, using in vivo microdialysis techniques.


METHODS
After intraperitoneal administration of 5 and 10 mg x kg(-10 of imipramine, the rats were anesthetized with 1 and 2.5% isoflurane inhalation. The control group was injected saline. Isoflurane anesthesia increased the extracellular concentration of dopamine metabolites without any change in dopamine concentration.


RESULTS
Under pretreatment of 5 mg x kg(-1) of imipramine, the effect of isoflurane on the change in dopamine and its metabolites was preserved. Whereas, 10 mg x kg(-1) of imipramine pretreatment induced a marked increase in the extracellular concentration of dopamine when only 1% isoflurane was applied but not with 2.5% isoflurane. In the rat administered 10 mg x kg(-1) of imipramine, anesthesia-induced increase of 3-methoxytyramine was not found.


CONCLUSIONS
Our previous investigation suggested that the isoflurane anesthesia has a biphasic effect on dopamine release in rat striatum under pargyline pretreatment. The same effect was shown in the rat administered imipramine. Isoflurane anesthesia might modify dopaminergic neural activity and release of neurotransmitters through different and complex ways.
Adachi
Yushi
Y
Intensive Care Unit, University Hospital, Hamamatsu University School of Medicine, Hamamatsu 431-3192.
Higuchi
Hideyuki
H
Watanabe
Kazuhiko
K
Kazama
Tomiei
T
Doi
Matsuyuki
M
Sato
Shigehito
S
D000769:Anesthesia, Inhalation; D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D007099:Imipramine / Q000494:pharmacology*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D000929:Antidepressive Agents, Tricyclic; D007530:Isoflurane; D007099:Imipramine; D004298:Dopamine