Acute methanol intoxication generates free radicals in rats: An ESR spin trapping investigation

Electron spin resonance (ESR) spectroscopy has been used to investigate fre e radical generation in rats with acute methanol poisoning. The spin trappi ng technique was used where a spin trapping agent, alpha-(4-pyridyl 1-oxide )N-tert-butylnitrone (POBN), reacted with the corresponding alcohol-derived or alcohol-dependent radical to from radical adducts. One radical adduct w as detected in both bile and urine samples 2 h after acute methanol poisoni ng in male Sprague Dawley rats. The hyperfine coupling constants for the ra dical adduct from [C-13]-labeled methanol detected in the bile were a(N) = 15.58, a(beta)(H) = 2.81 G, and a(beta)(13C) = 4.53 G, which unambiguously identified this species as POBN/(CH2OH)-C-.. The same radical adduct was de tected in urine. The identification of a methanol-derived radical adduct in samples from bile and urine provided strong direct evidence for the genera tion of the alcohol-derived radicals during acute intoxication by methanol. Simultaneous administration of the alcohol dehydrogenase inhibitor 4-methy lpyrazole and methanol resulted in an increase in the generation of the fre e radical metabolite detected in the bile. This is the first ESR evidence o f methanol-derived free radical generation in an animal model of acute meth anol intoxication. (C) 2000 Elsevier Science Inc.