title: Sex differences in nicotine sensitization and conditioned hyperactivity in adolescent rats neonatally treated with quinpirole: role of D2 and D3 receptor subtypes.
abstract: Neonatal quinpirole treatment in rats produces increased sensitivity of dopamine D2-like receptors throughout the animal's lifetime, referred to as D2 priming. There is little information on the effects of nicotine in adolescent rats, especially in a model that has clinical relevance to psychosis where increased D2 receptor sensitivity is common. Male and female rats were treated with quinpirole (1 mg/kg) or saline from postnatal (P) day 1-P21, given nicotine (0.5 mg/kg) or saline from P33 through P49, and placed into a locomotor arena for behavioral testing. Nicotine or saline treatment was preceded by the D2-like receptor antagonist eticlopride, D3 antagonist nafadotride, or saline. Conditioned hyperactivity was analyzed on P50 in the same context in a drug-free test. In females, D2 priming increased the locomotor response to acute nicotine, but did not affect subsequent nicotine sensitization, and only non-D2-primed females demonstrated conditioned hyperactivity. Eticlopride and nafadotride blocked behavioral sensitization, although nafadotride was more effective at blocking nicotine-conditioned hyperactivity in females. In males, D priming enhanced sensitization to nicotine and produced conditioned hyperactivity, which were blocked by eticlopride and nafadotride. These results have implications for psychosis and comorbidity of nicotine abuse in adolescence.
authors.affiliation: Department of Psychology, East Tennessee State University, Johnson City, TN 37614, USA.
authors.forename: Brianna
authors.initials: B
authors.lastname: Sheppard
authors.forename: Julia
authors.initials: J
authors.lastname: Lehmann
authors.forename: Zackary A
authors.initials: ZA
authors.lastname: Cope
authors.forename: Russell W
authors.initials: RW
authors.lastname: Brown
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000187:drug effects; D003213:Conditioning, Psychological / Q000187:drug effects; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D006948:Hyperkinesis; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009281:Naphthalenes / Q000494:pharmacology; D009538:Nicotine / Q000008:administration & dosage*; D011759:Pyrrolidines / Q000494:pharmacology; D019257:Quinpirole / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D050637:Receptors, Dopamine D3 / Q000502:physiology*; D012457:Salicylamides / Q000494:pharmacology; D012727:Sex Characteristics
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D009281:Naphthalenes; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D012457:Salicylamides; D019257:Quinpirole; D009538:Nicotine; C045989:eticlopride; C097285:nafadotride