Relation between voluntary ethanol intake in rats and changes in striatal muscarinic binding sites seen after induction of stable ethanol intake by an intermittent ethanol treatment.

Male rats were treated with ethanol (2.0 g/kg i.p.) once a week for approximately a year. They also had a choice between an ethanol solution (10%) and water as drinking fluid for 24 h prior to the injection. During the following evaluation period lasting around 40 weeks the rats had a continuous choice between ethanol and water as the drinking fluid. The ethanol concentration was varied with 10% as a standard. At sacrifice, muscarinic binding sites in the brain were determined. During the evaluation period the daily dose of ethanol varied considerably but the intake in each individual was remarkably stable independent of offered ethanol concentration. A highly significant regression was found between voluntary ethanol intake and muscarinic binding sites in the striatum (b = -0.003, r = -0.87, df = 8, P less than 0.005).