Selective breeding for divergence in novelty-seeking traits: heritability and enrichment in spontaneous anxiety-related behaviors.
Outbred Sprague-Dawley rats can be classified as high responders (HR) or low responders (LR) based on their levels of exploratory locomotion in a novel environment. While this novelty-seeking dimension was originally related to differential vulnerability to substance abuse, behavioral, neuroendocrine and gene expression studies suggest a fundamental difference in emotional reactivity between these animals. Here, we report the first study to selectively breed rats based on this novelty-seeking dimension. Response to novelty was clearly heritable, with a > 2-fold difference in behavior seen after eight generations of selection. Three tests of anxiety-like behavior consistently showed significantly greater anxiety in LR-bred rats compared to HR-bred animals, and this difference was diminished in the open field test by administration of the anxiolytic benzodiazepine drug, chlordiazepoxide. Cross-fostering revealed that responses to novelty were largely unaffected by maternal interactions, though there was an effect on anxiety-like behavior. These selected lines will enable future research on the interplay of genetic, environmental and developmental variables in controlling drug seeking behavior, stress and emotional reactivity.
Stead
John D H
JD
Institute for Neuroscience, Carleton University, Ottawa, ON, KIS 5B6, Canada. John_Stead@carleton.ca
Clinton
Sarah
S
Neal
Charles
C
Schneider
Johanna
J
Jama
Abas
A
Miller
Sue
S
Vazquez
Delia M
DM
Watson
Stanley J
SJ
Akil
Huda
H
D000818:Animals; D001007:Anxiety / Q000235:genetics*; D001522:Behavior, Animal; D001947:Breeding / Q000379:methods; D003624:Darkness; D005106:Exploratory Behavior / Q000502:physiology*; D014644:Genetic Variation; D005824:Genetics, Behavioral; D006801:Humans; D008027:Light; D018782:Maze Learning; D009043:Motor Activity / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012098:Reproduction / Q000235:genetics*