Effects of L-tryptophan and ethanol on sleep parameters in the rat.

Sleep parameters were monitored following (1) a single 2 g/kg oral dose of ethanol, (2) an oral dose of L-tryptophan (600 mg/kg), and (3) administration of both drugs simultaneously. Ethanol reduced REM and increased slow wave significantly. The effects of L-tryptophan were apparent only in the case of one parameter, REM latency. Administration of both drugs resulted in a significantly shorter REM latency than that observed for ethanol alone. Results are discussed in terms of possible changes in the biosynthesis of 5-HT.