Alcohol-induced euphoria: exclusion of serotonin.

During the first 30 min after acute ethanol consumption by three fasting normal male volunteers, no increase in circulating tryptophan availability to the brain occurred. On the contrary, a small decrease was observed, which became stronger subsequently. We conclude from this preliminary study that brain serotonin levels are not increased after alcohol intake by normal subjects and that, consequently, this indolylamine is unlikely to mediate the euphoric effects of alcohol.