The effect of ergotamine and methysergide on serotonin metabolism in the rat brain.
Ergotamine tartrate and methysergide maleate each significantly altered serotonin (5-HT) metabolism in the rat brain. Whole brain levels of 5-HT were markedly reduced in a dose-related manner, with peak activity observed 30 minutes after I.P. administration and persisting through four hours after dosing. In addition, turnover rate of 5-HT was significantly increased. Pentylenetetrazol (PTZ)-induced convulsions were not inhibited by either ergotamine or methysergide but each drug interacted with PTZ to induce lethality, which is suggestive evidence of central 5-HT antagonist activity. Moreover, regional distribution of 5-HT in the rat brain was altered by these drugs in such a way to suggest that neihter was a "universally acting" central 5-HT antagonist.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects; D004357:Drug Synergism; D004878:Ergotamine / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008784:Methysergide / Q000494:pharmacology*; D010433:Pentylenetetrazole / Q000494:pharmacology; D051381:Rats; D012640:Seizures / Q000139:chemically induced; D012701:Serotonin / Q000032:analysis / Q000378:metabolism*
D012701:Serotonin; D004878:Ergotamine; D010433:Pentylenetetrazole; D008784:Methysergide