| CHRONIC STRESS INDUCES DENDRITIC ALTERATIONS IN PYRAMIDAL
CELLS OF THE INFRALIMBIC CORTEX |
| D.S.Goldwater1,2*; C.Liston3;
M.M.Miller3; B.S.McEwen3; J.H.Morrison1,2
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| 1. Fishberg Department of Neuroscience, 2. Kastor Neurobiology
of Aging Laboratories, Mount Sinai School of Medicine, New York
City, NY, USA |
| 3. Rockefeller Univ., New York, NY, USA |
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Chronic stress has been shown to cause dendritic retraction
of pyramidal cells in the hippocampus (Watanabe et al., 1992). More
recently, loss of dendritic arbor in pyramidal cells within the anterior
cingulate cortex was demonstrated (Radley et al., 2004). In contrast,
chronic stress augments dendritic arbor in the lateral amygdala (Vyas
et al, 2002). Such morphologic adjustments could alter the connectivity
and balance of activity between these three regions, providing a substrate
for the long-term behavioral consequences of stress. We have now extended
this approach to the infralimbic cortex, a region known to modulate
the amygdala in the context of fear responses (Milad and Quirk, 2002).
We are investigating the effects of both chronic stress and potential
for reversibility of such effects on pyramidal cell morphology in
the infralimbic area of the prefrontal cortex. Rats were subjected
to 6 hours of daily restraint stress for 21 consecutive days. The
animals were then perfused either immediately after the 21 days of
stress or three weeks following the final day of restraint stress.
The infralimbic area was sectioned at 250 m and pyramidal neurons in layer II/III were injected
with Lucifer Yellow. 3-Dimensional reconstructions of the injected
neurons were carried out using Neurolucida in order to determine the
effects of chronic stress on total dendritic length, branch number,
and dendritic complexity, as well as the potential for these effects
to be reversed by an extended recovery period. Preliminary results
from Sholl analysis suggest chronic stress induces a retraction of
the most distal branches of the apical dendritic tree, particularly
between 270m and 360m from the cell body.
Additional analyses relevant both to chronic stress as well as the
potential reversibility of these effects are underway.
Support Contributed By: NIH grant MH58911
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