[Abstract Title]. - Society for Neuroscience

Topic: E.01.c. Steroids and plasticity
Support: NIH NS28421
NIH Predoctoral F31 MH78273
Title: The organizational role of androgens and the androgen receptor in anxiety-related
behaviors and sensorimotor gating
Authors: *D. G. ZULOAGA 1 , C. L. JORDAN 2 , S. M. BREEDLOVE 2 ;
1 Dept Psychol and Prog Neurosci, 2 Michigan State Univ., East Lansing, MI
Abstract: In rats, exposure to testosterone (T) early in life, which can act through both androgen
and estrogen receptors (ARs; ERs), organizes adult behaviors. In the current study we compared
behaviors in wild type (wt) male rats and AR deficient rats with the testicular feminization
mutation (Tfm), that were gonadectomized (Neo-Gdx) or sham-operated (Neo-Sham) on the day
of birth. In adulthood, rats were either gonadectomized or sham-operated and implanted with T
capsules to equilibrate adult circulating T and compared in tests of anxiety (open field, novel
object exposure, light dark box, elevated plus maze) and sensorimotor gating (prepulse inhibition
(PPI) of the acoustic startle response (ASR)). Compared to Neo-Sham rats, Neo-Gdx rats showed
decreased indices of anxiety in all tests with no differences between wt or Tfm males within
treatment groups. PPI was increased, while ASR was decreased in Neo-Gdx rats, with the
difference in ASR largely due to increased ASR in Neo-Sham Tfm males. Following behavior
testing, blood corticosterone levels were measured at baseline or 20 minutes after exposure to an
open field with a novel object. Corticosterone levels were elevated in Neo-Gdx rats at baseline
with no differences in novel object exposed rats. Analysis of brain weight revealed an effect of
neonatal castration largely due to heavier brains in Neo-Sham wt males compared to both Neo-
Gdx groups. These findings indicate a role of T prior to adulthood in the organization of anxietyrelated
behaviors and sensorimotor gating in rats, which appears to be primarily ARindependent.
Disclosures: D.G. Zuloaga, None; C.L. Jordan, None; S.M. Breedlove, None.
Poster
279. Steroids and Plasticity I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 279.6/MM20
Topic: E.01.c. Steroids and plasticity