Naltrexone, dopamine receptor agonists and antagonists, and food intake in rats: 2. 2-deoxy-D-glucose

• Published in: Pharmacology, biochemistry and behavior Vol. 49; no. 1; p. 205
• Main Authors: Schaefer, L A, Koch, J E, Bodnar, R J
• Format: Journal Article
• Language: English
• Published: United States 01-09-1994
• Subjects: 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine - pharmacology; Animals; Benzazepines - pharmacology; Deoxyglucose - pharmacology; Dopamine Agonists - pharmacology; Dopamine Antagonists - pharmacology; Eating - drug effects; Ergolines - pharmacology; Haloperidol - pharmacology; Male; Naltrexone - pharmacology; Quinpirole; Rats; Rats, Sprague-Dawley; Receptors, Dopamine D1 - drug effects; Receptors, Dopamine D2 - drug effects
• ISSN: 0091-3057
• DOI: 10.1016/0091-3057(94)90477-4

Significantly greater inhibition of deprivation-induced food intake occurs following cotreatment with naltrexone and either the D1 antagonist, SCH-23390, the D2 agonist, quinpirole, or the D2 antagonist, haloperidol, relative to naltrexone alone. Cotreatment with the D1 agonist, SKF-38393, failed to alter naltrexone's inhibition of deprivation-induced intake. The present study evaluated whether each of these D1 and D2 agonists and antagonists altered hyperphagia following 2-deoxy-D-glucose (2DG) themselves or in combination with naltrexone. Neither SKF-38393 (1-10 mg/kg) nor SCH-23390 (25-200 micrograms/kg) altered 2DG hyperphagia. Quinpirole (0.025-0.5 mg/kg) dose dependently decreased 2DG hyperphagia. 2DG hyperphagia was respectively increased and decreased by low (50 micrograms/kg) and high (500 micrograms/kg) doses of haloperidol. Cotreatment of SKF-38393 (0.1-1 mg/kg) and naltrexone potently enhanced the inhibition of 2DG hyperphagia relative to naltrexone alone. In contrast, cotreatment of naltrexone and either SCH-23390 (100-200 micrograms/kg) or quinpirole (0.025-0.05 mg/kg) inhibited 2DG hyperphagia in a manner similar to that of naltrexone alone. Finally, cotreatment of haloperidol (5-50 micrograms/kg) and naltrexone transiently enhanced the inhibition of 2DG hyperphagia relative to naltrexone alone.