%0 Journal Article
%T Brain Levels of Catalase Remain Constant through Strain, Developmental, and Chronic Alcohol Challenges
%A Dennis E. Rhoads
%A Cherly Contreras
%A Salma Fathalla
%J Enzyme Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/572939
%X Catalase (EC 1.11.1.6) oxidizes ethanol to acetaldehyde within the brain and variations in catalase activity may underlie some consequences of ethanol consumption. The goals of this study were to measure catalase activity in subcellular fractions from rat brain and to compare the levels of this enzyme in several important settings. In the first series of studies, levels of catalase were compared between juvenile and adult rats and between the Long-Evans (LE) and Sprague-Dawley (SD) strains. Levels of catalase appear to have achieved the adult level by the preadolescent period defined by postnatal age (P, days) P25¨CP28, and there were no differences between strains at the developmental stages tested. Thus, variation in catalase activity is unlikely to be responsible for differences in how adolescent and adult rats respond to ethanol. In the second series of studies, periadolescent and adult rats were administered ethanol chronically through an ethanol-containing liquid diet. Diet consumption and blood ethanol concentrations were significantly higher for periadolescent rats. Catalase activities remained unchanged following ethanol consumption, with no significant differences within or between strains. Thus, the brain showed no apparent adaptive changes in levels of catalase, even when faced with the high levels of ethanol consumption characteristic of periadolescent rats. 1. Introduction Ethanol consumption and subsequent oxidation lead to acetaldehyde production both peripherally and within the central nervous system [1]. Acetaldehyde appears to be a psychoactive substance with, for example, reinforcing properties that may be greater than that of ethanol itself [1¨C4]. Catalase (EC 1.11.1.6) is responsible for the majority of acetaldehyde production in the brain [5, 6]. Moreover, modulation of catalase levels can alter behavioral responses to ethanol, presumably by controlling levels of acetaldehyde [7¨C10] and/or by influencing the rate of ethanol elimination within the brain [11]. We are interested in whether natural variation in catalase between developmental stages might account for differences in behavioral responses to intoxicating doses of alcohol. Compared to adults, adolescent rats are less sensitive to loss of motor coordination, less sensitive to the sedative and anxiolytic effects of ethanol, and more sensitive to effects on memory [12¨C14]. These differences have been interpreted in light of ethanol itself, but relative levels of acetaldehyde production could be a complicating factor in this interpretation if, for example, catalase varied as a
%U http://www.hindawi.com/journals/er/2012/572939/