Estrogen facilitates fear conditioning and increases corticotropin-releasing hormone mRNA expression in the central amygdala in female mice.
Estrogens exert important actions on fear and anxiety-like behavior both in humans and non-human animals. Currently, the mechanisms underlying estrogenic modulation of fear are not known. However, evidence suggests that estrogens may exert their influence on fear within the amygdala. The purpose of the present study was to examine effects of estrogen on fear conditioning. Specifically, the present study examined whether long-term estrogen treatment in ovariectomized female mice via Silastic capsule implantation would facilitate both contextual and cued fear conditioning. In a separate set of experiments, we then examined whether estrogen treatment in ovariectomized female mice would modulate corticotropin-releasing hormone (CRH) gene expression within the amygdala. Long-term estrogen treatment facilitated both contextual and cued fear. Ovariectomized mice treated with estrogen froze significantly more to a context as well as to a discrete auditory cue. In addition, estrogen treatment significantly increased CRH mRNA expression within the central nucleus of the amygdala as measured by in situ hybridization and quantitative PCR. These data raise the possibility that estrogens could influence fear responses in females through their actions in the amygdala.
Jasnow
Aaron M
AM
Laboratory of Neurobiology and Behavior, Box 275, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. jasnowa@rockefeller.edu
Schulkin
Jay
J
Pfaff
Donald W
DW
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects*; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis* / Q000235:genetics; D003463:Cues; D004967:Estrogens / Q000494:pharmacology*; D005239:Fear / Q000187:drug effects*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D017403:In Situ Hybridization; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics
D004967:Estrogens; D012333:RNA, Messenger; D003346:Corticotropin-Releasing Hormone