Increased alcohol consumption in weight-reduced rats is modulated by the renin-angiotensin system

Weight reduction and food restriction increase the self-administration of alcohol and other drugs of abuse, but the underlying physiological mechanisms have not been identified. Because weight reduction alters angiotensin (ANG) II activity, and ANG II is known to modulate alcohol intake, ANG II may play a role in the enhanced alcohol consumption of food-deprived weight-reduced rats and in the drop in alcohol intake when these rats are refed. Two groups of rats were reduced to and maintained at 80% of their free feeding weights and offered daily 40 min access to a 6% (w/v) alcohol solution and water. Water was available ad lib. After alcohol intake stabilized, one group was given daily injections of the angiotensin converting enzyme inhibitor captopril (5.0 mg/kg) for 6 days while the other group received the saline vehicle. Following this, each group continued to receive either captopril or vehicle injections but was returned to ad lib feeding. Captopril did not alter alcohol intake when the rats were food-deprived and weight-reduced, but did significantly attenuate the decline in alcohol consumption compared to the vehicle group when both groups were refed and regaining weight. These findings suggest that the increase in alcohol intake with food restriction and its decline following refeeding are, in part, related to changes in ANG II activity.