Repeated exposure to social stress has long-term effects on indirect markers of dopaminergic activity in brain regions associated with motivated behavior

The visible burrow system (VBS) is a chronic social stress paradigm in which a dominance hierarchy forms among male rats housed with females. Males in the VBS undergo behavioral and physiological changes thought to be manifestations of chronic social stress. Since it is unclear whether chronic socia...

Full description

Saved in:
Bibliographic Details
Published in:Neuroscience 2004, Vol.124 (2), p.449-457
Main Authors: Lucas, L.R., Celen, Z., Tamashiro, K.L.K., Blanchard, R.J., Blanchard, D.C., Markham, C., Sakai, R.R., McEwen, B.S.
Format: Article
Language:English
Subjects:
Analysis of Variance
Animals
Autoradiography - methods
Basal Ganglia - anatomy & histology
Basal Ganglia - metabolism
Behavior, Animal
Binding Sites
Biological and medical sciences
Biomarkers
Corticosterone - metabolism
Dominance-Subordination
dopamine
Dopamine - metabolism
dopamine D1 receptor
dopamine D2 receptor
Dopamine Plasma Membrane Transport Proteins
dopamine transporter
enkephalin
Enkephalins - metabolism
Female
Fundamental and applied biological sciences. Psychology
In Situ Hybridization - methods
Male
Membrane Glycoproteins
Membrane Transport Proteins - metabolism
Motivation
Nerve Tissue Proteins - metabolism
Rats
Rats, Long-Evans
Receptors, Dopamine D1 - metabolism
Receptors, Dopamine D2 - metabolism
RNA, Messenger - metabolism
Social Behavior
Stress, Psychological - metabolism
Time
Vertebrates: nervous system and sense organs
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The visible burrow system (VBS) is a chronic social stress paradigm in which a dominance hierarchy forms among male rats housed with females. Males in the VBS undergo behavioral and physiological changes thought to be manifestations of chronic social stress. Since it is unclear whether chronic social stress affects motivation and reward behavior, brain areas related to these regions were examined. Long-term effects of a single or repeated VBS exposure on mesolimbic subregions were investigated by exposing rats to the VBS either once (one cycle of VBS housing and recovery) or repeatedly (three cycles). Behavior in the VBS was observed and rats were classified as dominants or subordinates. Subordinates were further sub-classified on the basis of stress hormone (corticosterone) response to an acute stressor (i.e. restraint stress). Normal responders were categorized as stress-responsive subordinates (SRS) and animals with a blunted hypothalamic–pituitary–adrenal axis response were designated as non-responsive subordinates (NRS). Controls males were pair-housed with a single female during VBS periods and alone during recovery. Lowered enkephalin-mRNA levels were observed in the nucleus accumbens (Acb) after single VBS exposure in SRS and repeated VBS exposure both subordinate groups (i.e. SRS+NRS) compared with controls. Decreased dopamine transporter density was detected after single VBS exposure in the dorsolateral caudate putamen (DLCPu) of NRS and after repeated VBS exposure in the Acb of NRS compared with controls. Dopamine D2 receptor density was elevated after single VBS exposure in the Acb of both subordinate groups (SRS+NRS) and after repeated VBS exposure in the DLCPu, dorsomedial CPu, and Acb of NRS compared with controls. No changes in dopamine D1 receptor binding were observed in any group. These results suggest that long-term changes in dopamine activity in mesolimbic structures persist after repeated exposures to chronic social stress and may provide insight into the neurochemical basis of depressive illness and subsequent comorbidity with drug abuse vulnerability.
ISSN:0306-4522
1873-7544
DOI:10.1016/j.neuroscience.2003.12.009