Abstract

The experimental induction of an apparent state of physiologic dependence on ethanol has been achieved in rhesus monkeys by the maintenance of relatively short periods of chronic ethanol intoxication. Animals were given 4 to 8 g/kg of ethanol (25% w/v) by gastric intubation in two or three fractional daily doses. In general, the blood-ethanol concentration fluctuated during 24-hour cycles over the range of 100 to 500 mg/100 ml, resulting in varying levels of intoxication. Termination of ethanol administration after 10 to 18 days of treatment resulted in the emergence, during the withdrawal periods, of a series of hyperexcitabiity signs which could be classified into tremulous, spastic and convulsive stages. The progressive severity of these stages could be correlated with declining blood-ethanol concentration. The convulsive threshold was reached prior to the complete disposal of ethanol. Both mild and severe abstinence reactions could be suppressed by ethanol administration. Signs in surviving animals that were untreated during withdrawal gradually subsided within 2 to 3 days, and thereafter these monkeys apparently reverted to normal states of behavior and neuromuscular tone. These observations suggest that an animal model of the biologic component of experimental alcoholism was induced in the rhesus monkey by this regimen of treatment.