Author: Arrant, A.E.; Schramm-Sapyta, N.L.; Kuhn, C.M.
Description: The light/dark (LD) test is a commonly used rodent test of unconditioned anxiety-like behavior that is based on an approach/avoidance conflict between the drive to explore novel areas and an aversion to brightly lit, open spaces. We used the LD test to investigate developmental differences in behavior between adolescent (postnatal day (PN) 28-34) and adult (PN67-74) male rats. We investigated whether LD behavioral measures reflect anxiety-like behavior similarly in each age group using factor analysis and multiple regression. These analyses showed that time in the light compartment, percent distance in the light, rearing, and latency to emerge into the light compartment were measures of anxiety-like behavior in each age group, while total distance traveled and distance in the dark compartment provided indices of locomotor activity. We then used these measures to assess developmental differences in baseline LD behavior and the response to anxiogenic drugs. Adolescent rats emerged into the light compartment more quickly than adults and made fewer pokes into the light compartment. These age differences could reflect greater risk taking and less risk assessment in adolescent rats than adults. Adolescent rats were less sensitive than adults to the anxiogenic effects of the benzodiazepine inverse agonist N-methyl-beta-carboline-3-carboxamide (FG-7142) and the alpha(2) adrenergic antagonist yohimbine on anxiety-like behaviors validated by factor analysis, but locomotor variables were similarly affected. These data support the results of the factor analysis and indicate that GABAergic and noradrenergic modulation of LD anxiety-like behavior may be immature during adolescence.
Subject headings: Adrenergic alpha-2 Receptor Antagonists/pharmacology; Age Factors; Animals; Antidepressive Agents/pharmacology; Anxiety/diagnosis/drug therapy; Carbolines/pharmacology; Exploratory Behavior/drug effects; Factor Analysis, Statistical; Light; Male; Motor Activity/drug effects; Neuropsychological Tests; Rats, Sprague-Dawley; Regression Analysis; Risk-Taking; Time Factors; Yohimbine/pharmacology; Adolescence; Anxiety; Fg-7142; Factor analysis; Light/dark test; Yohimbine
Publication year: 2013
Journal or book title: Behavioural Brain Research
Volume: 256
Pages: 119-127
Find the full text: https://www.strategian.com/fulltext/Arrant2013.pdf
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Type: Journal Article
Serial number: 1614