The effects of DL-5-hydroxytryptophan on ethanol consumption by rats

Rats were offered access to either distilled water or a 12% v/v solution of ethanol as their only fluid during a one hour period daily. After daily fluid consumption has achieved a stable baseline, either distilled water or DL-5-hydroxytryptophan (5HTP) in doses of 50, 100 or 200 mg/kg was injected intraperitoneally one hour prior to the drinking session. While each of the three doses of 5HTP caused a significant reduction in ethanol intake, distilled water had no effect. Water consumption was unaffected by 5HTP or distilled water injections. Varying the pretreatment interval from 0.5, 1, 4 to 8 hours for the 100 mg/kg 5HTP dose resulted in a significant decrease in ethanol consumption at 0.5 and 1 hour pretreatment intervals only. In approximately 25% of the rats tested, 5HTP resulted in a prolonged rejection of ethanol so severe that it resulted in death. Selected rats offered water during this ethanol rejection period readily drank it and survived.