Selective delta-opioid receptor antagonist N,N(CH3)2-Dmt-Tic-OH does not reduce ethanol intake in alcohol-preferring AA rats.
We studied the effect of a novel delta-opioid receptor antagonist N,N(CH(3))(2)Dmt-Tic-OH (Me(2)-Dmt-Tic-OH) on voluntary ethanol intake in an alcohol-preferring AA (Alko, Alcohol) rat line using a 4-hour limited access paradigm. Acute injections of Me(2)-Dmt-Tic-OH (10 and 30 mg/kg, i.p.) did not reduce 1-hour or 4-hour ethanol intake. Subtype non-selective opioid receptor antagonist naltrexone [0.1 and 0.3 mg/kg, subcutaneously (s.c.)] significantly reduced 1-hour ethanol drinking but had no effect on 4-hour ethanol consumption. Locomotor stimulation induced by the delta-opioid receptor agonist Tyr-D-Pen-Gly-Phe-D-Pen (DPDPE; 15 microg, intracerebroventricularly) was significantly attenuated by Me(2)-Dmt-Tic-OH (10 and 30 mg/kg, i.p.), which confirmed its efficacy as a delta-opioid receptor antagonist in rat brain. Our results support the idea that delta-opioid receptors do not mediate alcohol reward in AA rats.
Ingman
Kimmo
K
Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland. kiming@utu.fi
Salvadori
Severo
S
Lazarus
Larry
L
Korpi
Esa R
ER
Honkanen
Aapo
A
D000437:Alcoholism / Q000534:rehabilitation*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002755:Choice Behavior; D004151:Dipeptides / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D020881:Enkephalin, D-Penicillamine (2,5)- / Q000378:metabolism / Q000627:therapeutic use; D000431:Ethanol / Q000008:administration & dosage / Q000009:adverse effects*; D008124:Locomotion / Q000187:drug effects; D008297:Male; D009271:Naltrexone / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D051381:Rats; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*; D044005:Tetrahydroisoquinolines
D004151:Dipeptides; C434458:N,N-dimethyl-2',6'-dimethyltyrosyl-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic acid; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D044005:Tetrahydroisoquinolines; D000431:Ethanol; D009271:Naltrexone; D020881:Enkephalin, D-Penicillamine (2,5)-