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.
Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.
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Ståhle
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Collin
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Ungerstedt
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