effect of chronic acamprosate treatment on voluntary alcohol intake and betaendorphin plasma levels in rats selectively bred for high alcohol preference our previous studies have shown that repeated acamprosate administration to ethanolnaive warsaw high preferring whp rats resulted in increased plasma betaendorphin levels and at least partially prevents increases in levels of this peptide after a single administration of ethanol compared with untreated control rats the objective of the present study which included 45 whp rats was to continue the past research and investigate the effect of 10day acamprosate treatment 200 mgkg po on alcohol intake using a freechoice procedure and on changes in plasma betaendorphin levels while alcohol is available and 10 days after alcohol withdrawal voluntary alcohol consumption increases plasma levels of betaendorphin from 44025 pgml to 71157 pgml p00002 after a 10day of alcohol withdrawal the levels of this peptide were significantly reduced compared with levels in rats with free access to ethanol 71157 pgml vs 29438 pgml p0000001 and in control naive rats 44025pgml vs 29438pgml p0044 chronic treatment with acamprosate increased plasma betaendorphin levels both in whp rats with free access to ethanol 44025 pgml vs 61649 pgml p0008 and in rats after ethanol withdrawal 44025 pgml vs 62056 pgml p0007 in the group with free access to ethanol there was a significant reduction in mean ethanol intake from 675020 gkg body weightday to 468025 gkgday our results indicate that chronic acamprosate treatment may have beneficial effects as it increases the betaendorphin concentration thereby compensating for betaendorphin deficiency during ethanol withdrawal as the endogenous opioid system has an important role in the development of craving for alcohol restoring the alcoholinduced deficits in betaendorphin levels may be an important factor to prevent craving and maintaining abstinence we suppose that the anticraving mechanism of acamprosate that has been reported to abolish excessive glutamate release during alcohol withdrawal may be accompanied by compensation for the betaendorphin deficiency