Inhibition of drug-induced anorexia in rats by methysergide.
Iproniazid was found to reduce food consumption in fasting rats. Combined treatment of iproniazid with tryptophan resulted in a significantly greater anorexic action whilst tryptophan alone had no effect on food consumption. Iproniazid treatment was associated with a significant increase in brain 5-hydroxytryptamine (5-HT) concentration but in association with tryptophan higher brain 5-HT concentrations were recorded. The anorexic action of the iproniazid-tryptophan combination was antagonized in a dose-dependent fashion by methysergide. Equivalent levels of anorexia induced by fenfluramine and mazindol were similarly antagonized by methysergide in a dose-related manner. The results suggest a common role of 5-HT in the inhibition of eating behaviour in fasting rats when anorexia is induced by iproniazid, fenfluramine or mazindol, sensitive to a specific 5-HT antagonist.
D000818:Animals; D000855:Anorexia / Q000139:chemically induced / Q000188:drug therapy; D001066:Appetite / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005277:Fenfluramine / Q000037:antagonists & inhibitors; D007490:Iproniazid / Q000494:pharmacology; D008297:Male; D008454:Mazindol / Q000037:antagonists & inhibitors; D008784:Methysergide / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D012701:Serotonin / Q000032:analysis; D013997:Time Factors; D014364:Tryptophan / Q000494:pharmacology
D005277:Fenfluramine; D012701:Serotonin; D014364:Tryptophan; D008454:Mazindol; D007490:Iproniazid; D008784:Methysergide