title: Prepubertal Fischer 344 rats display stronger morphine-induced taste avoidance than prepubertal Lewis rats.
abstract: The present report asked if the previously reported differences in morphine-induced conditioned taste avoidance between adult F344 and LEW rats (F344 > LEW) are also evident in prepubescence (early adolescence). To assess this possibility, adult (Experiment 1) and prepubertal (Experiment 2) F344 and LEW rats were assessed for their ability to acquire morphine-induced taste avoidance (0, 3.2, 10, or 18 mg/kg) in a modified taste avoidance procedure. In each experiment, rats of both strains were given repeated pairings of saccharin and morphine followed by a final two-bottle avoidance test. Adult and prepubertal F344 subjects displayed a more rapid acquisition of the avoidance response as well as stronger suppression of consumption than their LEW counterparts. These data suggest the strains differ in their sensitivity to the aversive effects of morphine and that this differential sensitivity is evident early in development and is developmentally stable. The basis for these strain differences in morphine-induced avoidance was discussed.
authors.affiliation: Psychopharmacology Laboratory, Department of Psychology, American University, 4400 Mass. Ave., NW, Washington, DC, 20016. zacharyehurwitz@gmail.com.
authors.forename: Zachary E
authors.initials: ZE
authors.lastname: Hurwitz
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Cobuzzi
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Merluzzi
authors.forename: Bradley
authors.initials: B
authors.lastname: Wetzell
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Riley
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003213:Conditioning, Psychological / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D012439:Saccharin / Q000494:pharmacology; D013045:Species Specificity; D013649:Taste / Q000187:drug effects*
chemical_list: D009294:Narcotics; D009020:Morphine; D012439:Saccharin
keywords: F344; LEW; adult; development; early adolescence; morphine-induced taste avoidance; prepubertal; strain differences