Naltrexone, dopamine receptor agonists and antagonists, and food intake in rats: 2. 2-deoxy-D-glucose.
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.
Schaefer
L A
LA
Department of Psychology, Queens College, CUNY, Flushing 11367.
Koch
J E
JE
Bodnar
R J
RJ
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D004873:Ergolines / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009271:Naltrexone / Q000494:pharmacology*; D019257:Quinpirole; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000187:drug effects
D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D004873:Ergolines; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D009271:Naltrexone; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D003847:Deoxyglucose; D006220:Haloperidol