Loading…
Social Isolation‐Induced Decreases in Both the Abundance of Neuroactive Steroids and GABAA Receptor Function in Rat Brain
The effects of social isolation on behavior, neuroactive steroid concentrations, and GABAA receptor function were investigated in rats. Animals isolated for 30 days immediately after weaning exhibited an anxiety‐like behavioral profile in the elevated plus‐maze and Vogel conflict tests. This behavio...
Saved in:
Published in: | Journal of neurochemistry 2000-08, Vol.75 (2), p.732-740 |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | The effects of social isolation on behavior, neuroactive steroid concentrations, and GABAA receptor function were investigated in
rats. Animals isolated for 30 days immediately after weaning exhibited an
anxiety‐like behavioral profile in the elevated plus‐maze and Vogel conflict
tests. This behavior was associated with marked decreases in the
cerebrocortical, hippocampal, and plasma concentrations of pregnenolone,
progesterone, allopregnanolone, and allotetrahydrodeoxycorticosterone compared
with those apparent for group‐housed rats ; in contrast, the plasma
concentration of corticosterone was increased in the isolated animals. Acute
footshock stress induced greater percentage increases in the cortical
concentrations of neuroactive steroids in isolated rats than in group‐housed
rats. Social isolation also reduced brain GABAA receptor function,
as evaluated by measuring both GABA‐evoked Cl‐ currents in
Xenopus oocytes expressing the rat receptors and
tert‐[35S]butylbicyclophosphorothionate
([35S]TBPS) binding to rat brain membranes. Whereas the amplitude
of GABA‐induced Cl‐ currents did not differ significantly between
group‐housed and isolated animals, the potentiation of these currents by
diazepam was reduced at cortical or hippocampal GABAA receptors
from isolated rats compared with that apparent at receptors from group‐housed
animals. Moreover, the inhibitory effect of
ethyl‐β‐carboline‐3‐carboxylate, a negative allosteric modulator of
GABAA receptors, on these currents was greater at cortical
GABAA receptors from socially isolated animals than at those from
group‐housed rats. Finally, social isolation increased the extent of
[35S]TBPS binding to both cortical and hippocampal membranes. The
results further suggest a psychological role for neurosteroids and
GABAA receptors in the modulation of emotional behavior and mood. |
---|---|
ISSN: | 0022-3042 1471-4159 |
DOI: | 10.1046/j.1471-4159.2000.0750732.x |