Methionine enhances alcohol-induced narcosis in mice

Methionine is an essential amino acid that has been used as a therapeutic d rug in some disorders. In this study we questioned whether methionine affec ts ethanol-induced loss of righting reflex (narcosis), One hour after IP me thionine administration (60, 120, 240, 480, 720, 960, and 1280 mg/kg), mice were injected with ethanol (4.0 g/kg), and the duration of loss of rightin g reflex was recorded. Methionine! at the higher doses (960 and 1280 mg/kg) , significantly increased this effect on ethanol-treated animals. A time-co urse study revealed that methionine increased the duration of the loss of r ighting reflex induced by ethanol until 4 h after being injected. Because m ethionine did not affect blood ethanol levels, no change in peripheral alco hol can explain the observed effects. This potentiation was not specific fo r ethanol because methionine increased 3-methyl-1-butanol (0.6 g/kg) and l- propanol (2.4 g/kg)-induced loss of righting reflex as well. Therefore, the results obtained in this study suggest the need for further investigation into methionine-ethanol interactions prior to the use of methionine as an a gent that can be used as an antidepressant and to prevent damage to organic tissue in alcoholism. (C) 1999 Elsevier Science Inc.