title: Roles of dopaminergic innervation of nucleus accumbens shell and dorsolateral caudate-putamen in cue-induced morphine seeking after prolonged abstinence and the underlying D1- and D2-like receptor mechanisms in rats.
abstract: Drug-associated cues can elicit relapse to drug seeking after abstinence. Studies with extinction-reinstatement models implicate dopamine (DA) in the nucleus accumbens shell (NAshell) and dorsolateral caudate-putamen (dlCPu) in cocaine seeking. However, less is known about their roles in cue-induced opiate seeking after prolonged abstinence. Using a morphine self-administration and abstinence-relapse model, we explored the roles of NAshell and dlCPu DA and the D1/D2-like receptor mechanisms underlying morphine rewarding and/or seeking. Acquisition of morphine self-administration was examined following 6-Hydroxydopamine hydrobromide (6-OHDA) lesions of the NAshell and dlCPu. For morphine seeking, rats underwent 3 weeks' morphine self-administration followed by 3 weeks' abstinence from morphine and the training environment. Prior to testing, 6-OHDA, D1 antagonist SCH23390, or D2 antagonist eticlopride was locally injected; then rats were exposed to morphine-associated contextual and discrete cues. Results show that acquisition of morphine self-administration was inhibited by NAshell (not dlCPu) lesions, while morphine seeking was attenuated by lesions of either region, by D1 (not D2) receptor blockade in NAshell, or by blockade of either D1 or D2 receptors in dlCPu. These data indicate a critical role of dopaminergic transmission in the NAshell (via D1-like receptors) and dlCPu (via D1- and D2-like receptors) in morphine seeking after prolonged abstinence.
authors.affiliation: Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Zhu
authors.forename: Stephen
authors.initials: S
authors.lastname: Brimijoin
authors.forename: Nan
authors.initials: N
authors.lastname: Sui
mesh_terms: D000818:Animals; D001552:Benzazepines / Q000008:administration & dosage; D003463:Cues; D018492:Dopamine Antagonists / Q000008:administration & dosage*; D065127:Dopamine D2 Receptor Antagonists; D058999:Drug-Seeking Behavior / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D016627:Oxidopamine / Q000008:administration & dosage; D011699:Putamen / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D012457:Salicylamides / Q000008:administration & dosage
chemical_list: D001552:Benzazepines; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D012457:Salicylamides; D009020:Morphine; D016627:Oxidopamine; C045989:eticlopride