NALTREXONE PERSISTENTLY REDUCES RATS INTAKE OF A PALATABLE ALCOHOLIC BEVERAGE

Rats were given 30 days of opportunity to take a sweetened alcoholic b everage and water for 2 hr/day. At first, they took little alcohol, bu t subsequently took, on average, 2.3 g/kg of alcohol/daily session. Th ey also took sufficient water, during the 2-hr period, to maintain the ir health and to steadily gain weight. At the end of the 30 days, they were divided into four groups so that their intakes of alcohol were s imilar. All groups continued on the daily regimen, but each group rece ived different injections. One group received placebos, whereas the ot her two groups received either 5.0 or 10.0 mg/kg, respectively, of nal trexone daily, 30 min before the drinking session. The fourth group re ceived 5.0 mg/kg of naltrexone 12.5 hr before the session and another 5.0 mg/kg 30 min before the session. This regimen of dosing and daily opportunities to drink continued for 30 days. With the end of injectio ns, subjects continued on the regimen for another 5 days. Naltrexone, dose-relatedly, reduced rats' intake of alcoholic beverage. Furthermor e, with respect to reducing intake of alcohol, no tolerance or refract oriness were observed across the 30 days of dosing. Within a couple of days after dosing, levels of intake returned to predosing levels.