The caloric and intoxicating properties of fluid intake as components of stress-induced ethanol consumption in rats

Rats housed continuously in a test environment for 25 days were offered water, 5% v/v ethanol, 10% v/v ethanol, and propylene glycol at 7.5% w/v. The propylene glycol concentration represented a caloric midpoint between the 5 and 10% ethanol. After 10 baseline sessions, during which preference for the four solutions was shown to be statistically equal, shock schedules were introduced. The consumption of ethanol at both concentrations showed significant peaks for the interval immediately following 12 min of shock each hour. Intake peaks were not observed for the water or propylene glycol. Baseline blood alcohol levels were negligible, but blood levels under shock averaged 143 mg/dl and ranged from 45.0 mg/dl to 295.0 mg/dl. After the shock sessions were terminated, baseline drinking indicated no significant change in preference relative to pre-shock baselines, but there was an elevation in preference for 5% ethanol relative to the other fluids. The preference for propylene glycol or water did not change.