TY - JOUR
T1 - Serotonin, but not dopamine, metabolites are increased in selected brain regions of subordinate male rats in a colony environment
AU - Blanchard, D. Caroline
AU - Cholvanich, Panrapee
AU - Blanchard, Robert J.
AU - Clow, Daniel W.
AU - Hammer, Ronald P.
AU - Rowlett, J. K.
AU - Bardo, Michael T.
PY - 1991/12/24
Y1 - 1991/12/24
N2 - Subordinate male laboratory rats maintained in mixed-sex groups in a Visible Burrow System habitat show a complex pattern of stress-related changes including enhanced defensive behavior, early mortality and increased voluntary ethanol consumption. Analysis of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels indicated that 5-HT levels do not differ between colony subordinates, colony dominants, and singly-housed control animals. However, 5-HIAA levels were higher in subordinates than either dominants or control animals in the preoptic area, amygdala, hippocampus, and spinal cord, and, were higher than dominants only, in entorhinal cortex. Subordinates' regional 5-HIAA/5-HT ratios were reliably higher than those of dominant or control animals in midbrain and spinal cord and reliably higher than dominants only, in hypothalamus. Dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) levels and DA/DOPAC ratios were affected neither in hypothalamus nor midbrain. These findings suggest that a consistent increase of 5-HIAA levels in selected brain regions of subordinate rats may represent a biological substrate for a well-characterized pattern of alterations in defensive behaviors for these animals.
AB - Subordinate male laboratory rats maintained in mixed-sex groups in a Visible Burrow System habitat show a complex pattern of stress-related changes including enhanced defensive behavior, early mortality and increased voluntary ethanol consumption. Analysis of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels indicated that 5-HT levels do not differ between colony subordinates, colony dominants, and singly-housed control animals. However, 5-HIAA levels were higher in subordinates than either dominants or control animals in the preoptic area, amygdala, hippocampus, and spinal cord, and, were higher than dominants only, in entorhinal cortex. Subordinates' regional 5-HIAA/5-HT ratios were reliably higher than those of dominant or control animals in midbrain and spinal cord and reliably higher than dominants only, in hypothalamus. Dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) levels and DA/DOPAC ratios were affected neither in hypothalamus nor midbrain. These findings suggest that a consistent increase of 5-HIAA levels in selected brain regions of subordinate rats may represent a biological substrate for a well-characterized pattern of alterations in defensive behaviors for these animals.
KW - 5-Hydroxyindoleacetic acid
KW - Animal model
KW - Depression
KW - Serotonin
KW - Subordination
KW - defensive behavior
UR - http://www.scopus.com/inward/record.url?scp=0026331918&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026331918&partnerID=8YFLogxK
U2 - 10.1016/0006-8993(91)91379-F
DO - 10.1016/0006-8993(91)91379-F
M3 - Article
C2 - 1726073
AN - SCOPUS:0026331918
SN - 0006-8993
VL - 568
SP - 61
EP - 66
JO - Brain Research
JF - Brain Research
IS - 1-2
ER -