MODULATION OF VOLITIONAL ETHANOL INTAKE IN THE RAT BY CENTRAL DELTA-OPIOID RECEPTORS

The acute effect of opioid antagonists on volitional ethanol intake wa s studied in unselected Sprague-Dawley rats using a two-bottle, free-c hoice model. The total daily intake of ethanol during saline treatment was 1.79 +/- 0.4 g/kg/day (n = 136). The rats were deprived of fluids for the last 4 hr of the light period. Saline or drug was given intra peritoneally 20 to 30 min before the onset of dark, and the ethanol an d water intakes were measured during the following hour. The ethanol i ntake during this hour was 0.75 +/- 0.06 g/kg (n = 136). Naltrexone si gnificantly reduced ethanol intake. There was also a significant reduc tion in ethanol intake following administration of ICI-174,864. Naloxo nazine and naloxone methiodide lacked effect. None of the treatments h ad any effect on the water or food intake. The results suggest that ce ntral delta-opioid receptors modulate volitional ethanol intake in the rat.