Effects of acute cocaine treatment on the turnover of 5-hydroxytryptamine in the rat brain.
1. The effects of cocaine (20 mg/kg s.c.) on 5-hydroxytryptamine (5-HT) turnover were examined in rats. 2. In vivo cocaine administration resulted in decreased turnover of 5-HT, as indicated by the decreased accumulation of 5-HT after pargyline administration and the decreased accumulation of 5-hydroxyindoleacetic acid (5-HIAA) following probenecid injection. 3. A time-related decrease in 5-HIAA concentrations and a small fall in 5-HT concentrations in the whole brain were observed following the acute administration of cocaine hydrochloride (20 mg/kg). Tryptophan levels were found to be slightly decreased in the brain. 4. Enhanced reactivity, but neither stereotypy nor hyperthermia, was observed following cocaine injection (20 mg/kg). 5. It is concluded that cocaine inhibits the turnover of brain 5-HT and that this action of cocaine may be responsible for the differences in a number of pharmacological effects between cocaine and amphetamine.
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D008297:Male; D008996:Monoamine Oxidase Inhibitors; D010293:Pargyline / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000032:analysis / Q000378:metabolism*; D014364:Tryptophan / Q000032:analysis / Q000097:blood
D008996:Monoamine Oxidase Inhibitors; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D010293:Pargyline; D000661:Amphetamine; D003042:Cocaine; D011339:Probenecid