Dopamine-dependent behavioural stimulation by non-peptide delta opioids BW373U86 and SNC 80: 2. Place-preference and brain microdialysis studies in rats.
The motivational properties of the non-peptide delta-opioid receptor agonists BW373U86 and SNC 80 were investigated using the place-conditioning paradigm. BW373U86 (0.5-1.0 mg/kg s.c.) and SNC 80 (1.25-5.0 mg/kg s.c.) elicited significant preference for the drug-paired compartment, in a dose-related fashion. Naltrindole (5.0 mg/kg s.c.) pretreatment, while failing to modify preference when given alone, completely prevented place-preference induced by BW373U86 (1.0 mg/kg s.c.) and SNC 80 (1.25 mg/kg s.c.). The dopamine D1 receptor antagonist SCH23390, given at doses that do not affect place-preference (0.012 mg/kg s.c.), completely prevented the place-preference induced by BW373U86 and SNC 80. At the doses effective in eliciting place-preference, BW373U86 and SNC 80 failed to modify extracellular dopamine in the medial nucleus accumbens, while in the dorso-lateral caudate-putamen BW373U86 (1.0 and 2.5 mg/kg s.c.) reduced extracellular dopamine, and this effect was prevented by naltrindole (5.0 mg/kg s.c.). SNC 80, only at the dose of 5 mg/kg s.c., significantly reduced extracellular DA in the dorso-lateral caudate-putamen. The results indicate that stimulation of delta-opioid receptors has incentive properties that might be related to an indirect amplification of post-synaptic dopamine transmission.
Longoni
R
R
Department of Toxicology, University of Cagliari, Italy.
Cadoni
C
C
Mulas
A
A
Di Chiara
G
G
Spina
L
L
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D001549:Benzamides / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology; D001923:Brain Chemistry / Q000187:drug effects*; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D003216:Conditioning, Operant / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001549:Benzamides; D001552:Benzazepines; D018492:Dopamine Antagonists; D009292:Narcotic Antagonists; D010879:Piperazines; C083877:BW 373U86; C088464:4-(alpha-(4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N,N-diethylbenzamide; D009271:Naltrexone; C055382:naltrindole; D004298:Dopamine