title: Microinjection of the delta-opioid receptor selective antagonist naltrindole 5'-isothiocyanate site specifically affects cocaine self-administration in rats responding under a progressive ratio schedule of reinforcement.
abstract: Whether the delta-opioid receptor (DOR) system can modulate behavioral effects of cocaine remains equivocal. We examined whether site- and subtype-selective blockade of DORs within the rat mesocorticolimbic system affects cocaine self-administration. The DOR antagonist naltrindole 5'-isothiocyanate (5'-NTII; 5nmol) was microinjected into the nucleus accumbens (NAcc), ventral tegmental area (VTA), or amygdala (AMYG) in rats self-administering 1.5mg/kg cocaine under a progressive ratio (PR) schedule. Intra-NAcc 5'-NTII significantly decreased cocaine self-administration, while 5'-NTII administration into the VTA significantly increased cocaine-maintained responding. 5'-NTII administration into the AMYG produced no effect. These data support a site-specific role of DORs in cocaine's behavioral effects.
authors.affiliation: Department of Pharmaceutical Sciences, Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, PA 19140, USA. saraward@temple.edu
authors.forename: Sara Jane
authors.initials: SJ
authors.lastname: Ward
authors.forename: David C S
authors.initials: DC
authors.lastname: Roberts
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects; D003042:Cocaine / Q000008:administration & dosage*; D017879:Isothiocyanates / Q000494:pharmacology*; D008297:Male; D008845:Microinjections / Q000379:methods; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors*; D012055:Reinforcement Schedule; D012646:Self Administration / Q000379:methods; D013997:Time Factors
chemical_list: D000779:Anesthetics, Local; D017879:Isothiocyanates; D017465:Receptors, Opioid, delta; C064283:naltrindole 5'-isothiocyanate; D009271:Naltrexone; D003042:Cocaine