ALCOHOL DEPENDENCE INDUCED IN RATS BY SEMIVOLUNTARY INTERMITTENT INTAKE

The objective of the present experiment was to assess ethyl alcohol (E TOH) dependence brought about by a semivoluntary intermittent intake r egimen in rats. Male Wistar rats weighing 150-250 g at the onset of th e experiment were assigned to the following groups: 0% ETOH (N = 11), 5% ETOH (N = 20), 20% ETOH CN = 20) and 40% ETOH (N = 18). ETOH soluti ons were offered at the end of the day and overnight from Monday to Fr iday, and throughout weekends, for 90 days. The concentration of the E TOH solutions was increased in a stepwise fashion allowing the rats to get used to the taste of alcohol. Reposition of pure water was permit ted during 1-h water drinking periods in the morning. Daily volume int ake (+/- SEM) averaged 25.4 +/- 0.4 ml (0% ETOH), 23.8 +/- 0.6 ml (5% ETOH), 17.6 +/- 0.7 ml (20% ETOH) and 17.5 +/- 0.6 ml (40% ETOH). ETOH consumption differed significantly (P<0.05) among groups, averaging 4 .4 +/- 0.2 g kg(-1) day(-1) (5% ETOH), 10.3 +/- 0.3 g kg(-1) day(-1) ( 20% ETOH) and 26 +/- 1.2 g kg(-1) day(-1) (40% ETOH). Furthermore, ETO H detection in plasma 10-12 h after offering the solution indicated th at its consumption in the 40% ETOH group was sufficient to override it s metabolism. Overt signs of ETOH dependence, such as increased thirst , hyperactivity, puffing, hair ruffling and startle responsiveness as well as reduced drowsiness, were significantly increased in the 20% an d 40% ETOH groups compared to the 0% and 5% groups. Accordingly, the m odel described here proved to be a useful tool for the evaluation of s ubtle or moderate behavioral and physical consequences of long-term ET OH intake.