title: Correspondence of increased debrisoquine 4-monooxygenase activity with seizure-susceptibility in Mongolian gerbils.
abstract: Four drug-metabolizing activities in Wistar rat and Mongolian gerbil liver microsomes were investigated to clarify the biochemical basis of convulsions. No significant associations were observed between the susceptibility to the tonic-clonic seizures in Mongolian gerbils and the drug-metabolizing enzymatic activities of p-nitroanisole O-demethylase, aminopyrine demethylase and benzo[a]pyrene-3-monooxygenase. However, a significant association was observed with the debrisoquine 4-monooxygenase (cytochrome P-450db1-linked monooxygenase system) activity, which is known to metabolize exogenous and endogenous parkinsonism-inducing neurotoxins such as MPTP and TIQ, and to activate carcinogens during the detoxication of xenobiotics. The mean activity of debrisoquine 4-monooxygenase in the seizure-sensitive group (male, 380; female, 350 pmol/h/mg protein) remained significantly higher (about 4-5 times) than that in the seizure-resistant group (male, 90; female, 80 pmol/h/mg protein). More Mongolian gerbils were extensive metabolizers of debrisoquine in the seizure-sensitive group than in the seizure-resistant group. These results suggest a possibility that the cytochrome P-450db1-linked monooxygenase system may activate the potential neurotoxins which are associated with tonic-clonic seizures in the Mongolian gerbil.
authors.affiliation: Department of Neuropsychiatry, University Hospital, Kagawa Medical School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Iwahashi
authors.forename: H
authors.initials: H
authors.lastname: Suwaki
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Y
authors.initials: Y
authors.lastname: Ichikawa
authors.forename: K
authors.initials: K
authors.lastname: Hosokawa
mesh_terms: D000818:Animals; D019389:Cytochrome P-450 CYP2D6; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004569:Electroencephalography; D005260:Female; D020022:Genetic Predisposition to Disease; D005849:Gerbillinae / Q000235:genetics / Q000378:metabolism; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000201:enzymology* / Q000209:etiology
chemical_list: D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019389:Cytochrome P-450 CYP2D6