title: Novelty response of rats determines the effect of prefrontal alpha-2 adrenoceptor modulation on anxiety.
abstract: In this study we provide evidence that animals of the same population, although identical in age and sex, have individual reactions to the prefrontal modulation of adrenoceptors. We have examined the dose-dependent action of α(2)-adrenoceptor agents on the anxiety of rats with different response to novelty in the elevated plus maze (EPM) apparatus. Rats were divided into high (HR) and low responder (LR) groups based on their locomotor activity in a novel open field environment. HR rats also showed increased locomotion and low anxiety in the EPM. Prefrontal injection of α(2)-receptor antagonist yohimbine, BRL44408 or imiloxan caused anxiety only in HR rats. The α(2A/D)-receptor agonist guanfacine increased anxiety levels of both groups. However, the effective dose was lower in HR rats. The present results propose different prefrontal adrenoceptor sensitivity of rats showing distinct baseline activity levels.
authors.affiliation: Department of Experimental Zoology and Neurobiology, University of Pécs, 6. Ifjúság Str., H-7624, Pécs, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Uzsoki
authors.forename: M
authors.initials: M
authors.lastname: Tóth
authors.forename: I
authors.initials: I
authors.lastname: Hernádi
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000494:pharmacology; D058669:Adrenergic alpha-2 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D001007:Anxiety / Q000139:chemically induced* / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology*; D016316:Guanfacine / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007206:Individuality; D054833:Isoindoles / Q000494:pharmacology; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D007093:Imidazoles; D054833:Isoindoles; D018341:Receptors, Adrenergic, alpha-2; D015016:Yohimbine; D016316:Guanfacine; C072125:BRL 44408; C044484:Imiloxan