Enhanced conditioned approach responses in transgenic mice with impaired glucocorticoid receptor function.
The long-term consequences of impaired glucocorticoid receptor (GR) function on reward-related learning were studied in transgenic mice with impaired GR function in a series of experiments taxing conditioned and unconditioned approach responses to stimuli predictive of food. There was a double-dissociation in that transgenic mice with impaired GR activity showed enhanced conditioned exploration in situations when stimuli predicted reward, while free-feeding food consumption over 24 h was reduced. Previous experiments have shown altered accumbens dopaminergic activity in these animals. In line with these findings, we observed an enhanced behavioural stimulation of transgenic mice following administration of d-amphetamine (2 mg/kg). This suggests that the increase in preparatory responses in transgenic mice may be mediated via an enhanced accumbens dopaminergic activity, possibly secondary to alterations in other brain systems.
Steckler
T
T
Max Planck Institute of Psychiatry, Munich, Germany. steckler@mpipsykl.mpg.de
Holsboer
F
F
D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology*; D001143:Arousal / Q000187:drug effects / Q000502:physiology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D009042:Motivation; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology; D011965:Receptors, Glucocorticoid / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D011965:Receptors, Glucocorticoid; D003913:Dextroamphetamine; D004298:Dopamine