Effects of halothane anaesthesia on extracellular levels of dopamine, dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindolacetic acid in rat striatum: a microdialysis study.
The effects of halothane anaesthesia on striatal extracellular levels of dopamine, dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindolacetic acid (5HIAA) were investigated in microdialysis experiments. Induction of anaesthesia was accompanied by a rapid increase in dopamine levels and a slower increase in DOPAC and HVA. 5HIAA was not affected. The reduction of dopamine levels induced by apomorphine 0.05 mg/kg appeared with a shorter latency in conscious rats than in anaesthetised rats but the maximum decrease was unaffected by anaesthesia. The decreases in dopamine and DOPAC induced by alpha-methyl-p-tyrosine 50 mg/kg were affected in opposite directions by halothane: the dopamine reduction was more pronounced while the DOPAC reduction was less pronounced in anaesthetized than in conscious animals. In no case was a qualitative shift in the response observed. It is concluded that halothane may influence the levels of dopamine as well as the response to dopaminergic drugs.
Ståhle
L
L
Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.
Collin
A K
AK
Ungerstedt
U
U
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism*; D000758:Anesthesia; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D006221:Halothane; D006719:Homovanillic Acid / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013238:Stereotaxic Techniques; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D015102:3,4-Dihydroxyphenylacetic Acid; D006897:Hydroxyindoleacetic Acid; D019805:alpha-Methyltyrosine; D001058:Apomorphine; D006221:Halothane; D004298:Dopamine; D006719:Homovanillic Acid