Resumo

OBJECTIVE: Ethanol chronic ingestion induces several changes on the central nervous system leading to cognitive impairment and behavioral alterations. The aim of this work was to investigate whether chronic ingestion of ethanol affects the spatial memory in rats. METHODS: Male Wistar rats (150g, n=11-12) were treated with water (control) or 5%-20% of ethanol, increasing 5% per week (habituation), and 20% maintained for 90 days (chronic ingestion) before testing. The levels of anxiety and the spatial memory were analyzed on the elevated plus-maze (EPM). Behavioral responses were scored for 5min: number of entries and time on the open arms, number of entries and time on the closed arms, number of stretched attend postures (SAPs). Animals were retested after 24 hours. Groups were compared by Student t-tests and the level of significance was set at p<0.05. RESULTS: Ethanol chronic ingestion induced a dramatic increase in both number of entries (127%) and time (150%) in the open arms on the first test (p<0.05). A significant reduction was seemed in both scores in the open and closed arms (36-74%, p<0.05) when the control animals were re-exposed to EPM 24 hours later. However, the chronic ingestion of ethanol induced a significant reduction only in the number of entries (39%) and time (54%) in the open arms (p<0.05) when the animals were re-exposed to EPM. An increase was seemed in the time spent in the closed arms (32,5%, p<0.05). No change was induced by ethanol chronic ingestion in the number of entries in the closed arms. No changes were found in the number of SAPs when the controls and alcoholic animals were re-tested either. CONCLUSION: Long period of ethanol chronic ingestion has an anxiolytic-like effect and also, may affect the spatial memory. Committee on Animal Research and Ethics(CEUA-School of Medicine of Catanduva): 02/08 Financial Support: Fundação Padre Albino.