Induction of physical dependence upon ethanol in rats using intravenous infusion.

Intravenous infusions were used to produce physical dependence upon ethanol in rats. The procedure proved to be safe, rapid, and reliable. Ethanol (30% v/v) was administered over a 7-day period. The mean daily dose ranged from 10--14 g/kg/day. Control rats were exposed to a comparable procedure except that saline, rather than ethanol, was infused. All ethanol treated rats that survived the intoxication period (n = 11) showed signs of physical dependence (moderate to severe, n = 8; mild, n = 3) following ethanol withdrawal. Saline treated rats (n = 8) did not show any of these symptoms. The most reliable ethanol withdrawal signs observed were: spontaneous seizure (n = 7), audiogenic seizure (n = 7), tremors (n = 6), tail stiffening (n = 10) and body rigidity (n = 9). These symptoms were analyzed in terms of their hour of onset and hour of maximum intensity following ethanol withdrawal. Application of the intravenous method for the study of ethanol self-administration is discussed.