THE EFFECTS OF SINGLE AND REPEATED EPISODES OF THIAMIN DEFICIENCY ON MEMORY IN ALCOHOL-CONSUMING RATS

The underlying pathogenesis of Korsakoff's syndrome, an amnesic disord er most commonly found in alcoholics, is not well understood. Chronic alcoholism is associated with thiamin deficiency and current thinking is that this may be the causal factor. In Experiment 1, rats were give n a 20% (v/v) ethanol/water mix as their only source of fluid for 156 days. Three groups were made thiamin deficient through the combination of a thiamin-deficient diet and the centrally acting thiamin antagoni st pyrithiamin hydrobromide, after 4, 15, and 26 weeks exposure to eth anol, respectively. The control group was given ad lib access to labor atory chow and water throughout this period. There were no differences between groups on either the working or reference versions of the Mor ris water tank paradigm. In Experiment 2, to test the hypothesis that a single bout of thiamin deficiency, with or without concurrent alcoho l intake, is not sufficient to cause severe memory impairments, two gr oups of rats were subjected to three bouts of thiamin deficiency. One of these groups consumed an ethanol/water mix, the other tap water. A third group was made thiamin deficient on only one occasion. The contr ol group was not made thiamin deficient and consumed lab chow and tap water throughout. Once again, there were no between-group differences in the data derived from testing in either the eight-arm radial maze o r the Morris water tank task. These experiments indicate that the aeti ology of Korsakoff's syndrome is more complex than previously thought. Copyright (C) 1997 Elsevier Science Inc.