[Abstract Title]. - Society for Neuroscience

activation on principal cell dendrites, may more readily transmit excitatory signals than their
diestrus or male counterparts. These findings suggest that ovarian steroids can alter hippocampal
excitability through direct effects on DORs in principal cells. Analysis of DOR trafficking
changes in interneurons is underway to determine if DORs, like MORs, are also positioned to
facilitate indirect excitation of principal cells.
Disclosures: T.J. Williams, None; A. Torres-Reveron, None; T.A. Milner, None.
Poster
279. Steroids and Plasticity I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 279.10/MM24
Topic: E.01.c. Steroids and plasticity
Support: NIH Grant MH41256
The Gary R. Helman Foundation
Title: Dynamic regulation of hippocampal histone H3 methylation by acute stress
Authors: *R. G. HUNTER 1 , K. J. MCCARTHY 1 , T. A. MILNE 2 , R. D. ROMEO 3 , E. M.
WATERS 1 , C. ALLIS 2 , B. S. MCEWEN 1 ;
1 Lab. Neuroendocrinol, 2 Lab. of Chromatin Biol. and Epigenetics, Rockefeller Univ., New York,
NY; 3 Psychology, Barnard Col., New York, NY
Abstract: Modification of epigenetic histone marks has been observed in a number of models of
human neurological and mental disorders such as ischemia, drug abuse and depression, all of
which are influenced by stress and the actions of corticosteroid hormones. Here we examine the
effect of both acute and chronic stress as well as acute and chronic corticosterone on the
methylation status of histone H3 lysine 9 (H3K9). In our studies we used acute and chronic (21
day) restraint stress as well as acute (10mg/kg s.c.) and chronic corticosterone (400ug/ml
dissolved in drinking water with 2.5% ETOH) on the levels of H3K9 trimethylation, a marker of
transcriptional repression in the hippocampal formation of the male rat. We found that the
chronic manipulations produced small to non-significant reductions in H3K9 trimethylation. In
contrast, acute restraint produced a robust (114 ±45%, p