Modulation of Volitional Ethanol Intake in the Rat by Central δ-Opioid Receptors

Authors

  • Johan Franck,

    Corresponding author
    1. Departments of Clinical Neuroscience (J.F., S.L., P.R) and Physiology and Pharmacology (J.F.), Karolinska Institute, Stockholm, Sweden.
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  • Sara Lindholm,

    1. Departments of Clinical Neuroscience (J.F., S.L., P.R) and Physiology and Pharmacology (J.F.), Karolinska Institute, Stockholm, Sweden.
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  • Pauline Raaschou

    1. Departments of Clinical Neuroscience (J.F., S.L., P.R) and Physiology and Pharmacology (J.F.), Karolinska Institute, Stockholm, Sweden.
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  • This study was supported by the Alcohol Research Council of the Swedish Alcohol Retail Monopoly, Stifielsen Lars Hiertas Minnesfond, the Swedish MRC (14X-07164), and by fun & from the Karolinska Institute.

Reprint requests: Johan Franck, Department of Physiology and Pharmacology, Karolinska Institute, S-171 77 Stockholm, Sweden.

Abstract

The acute effect of opioid antagonists on volitional ethanol intake was studied in unselected Sprague-Dawley rats using a two-bottle, free-choice 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 intraperitoneally 20 to 30 min before the onset of dark, and the ethanol and water intakes were measured during the following hour. The ethanol intake during this hour was 0.75 ± 0.06 g/kg (n= 136). Naltrexone significantly reduced ethanol intake. There was also a signiflcant reduction in ethanol Intake following administration of ICI-174,864. Naloxonazine and naloxone methiodide lacked effect. None of the treatments had any effect on the water or food intake. The resutts suggest that central bopioid receptors modulate volitional ethanol intake in the rat.

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