Ontogeny of ethanol elimination and ethanol-induced hypothermia

Ontogeny of ethanol elimination rates and ethanol-induced hypothermia were examined as possible mechanisms contributing to the marked reduction in eth anol sensitivity early in life (Little et al., 1996; Silveri & Spear, 1998) and the notable gender difference in ethanol sleep-time seen in adult anim als (Silveri & Spear, 1998). Elimination rates and brain/blood ethanol leve ls were determined following doses of 1.5 or 4.5 g/kg ethanol in male and f emale Sprague-Dawley rats at postnatal days (P)16, 26, 36, or 56. Animals w ere sacrificed at 40, 80, or 160 min post-injection, with ethanol eliminati on rates estimated from the slope of the regression of blood and brain alco hol levels across the three sampling periods. P16 animals exhibited the slo west rate of ethanol metabolism, while no gender effects were evident at an y age. Observed ontogenetic increases in ethanol hypothermia were not syste matically related to the ontogeny of ethanol metabolism. Factors other than ontogenetic changes in ethanol metabolism, hypothermia, or the distributio n of ethanol between brain and blood must underlie the relative insensitivi ty to ethanol often reported in young and adolescent organisms, a fruitful area for future studies given the frequent use and misuse of alcohol by hum an adolescents. (C) 2000 Elsevier Science Inc. All rights reserved.