RESUMO
The most dangerous characteristic of alcohol is the ease with which it induces dependence in the regular drinkers. The present study tested the hypothesis that a continuously sustained elevation of relatively high blood ethanol concentrations by forced intragastric administration for only a few days may prove adequate, and is an essential condition for rapid inducation of physical dependence upon ethanol in rats. It also describes the signs and reactions of ethanol detoxication phase and dependence phase of the withdrawal period. Rats were treated by intragastric intubation of a 20% ethanol solution in doses of 9-15 g/kg in 3-5 fractions for 16 days. Both tolerance and physical dependence were demonstrated after this treatment with the maximum tolerable doses to only a few days. Tolerance was assessed by signs of severity of intoxication. During withdrawal, as blood ethanol concentrations approached 100mg/dl the ethanol dependence phase was characterized by the onset of signs and responses of progressive severity. A significant degree of tolerance was demonstrated for all signs of intoxication after 4 days of treatment. The severity of the withdrawal reactions intensified progressively to a maximum intensity after 4 days of treatment. These different time courses suggest that tolerance and physical dependence are mediated through different mechanisms