Chronic stress, cyclic 17β-estradiol, and daily handling influences on fear conditioning in the female rat

A. N. Hoffman, Charles E. Armstrong, Jeffery J. Hanna, Cheryl Conrad

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Chronic stress and estrogens alter many forebrain regions in female rats that affect cognition. In order to investigate how chronic stress and estrogens influence fear learning and memory, we ovariectomized (OVX) female Sprague-Dawley rats and repeatedly injected them (s.c.) with 17β-estradiol (E, 10 μg/250. g or sesame oil vehicle, VEH). Concurrently, rats were restrained for 6. h/d/21. d (STR) or left undisturbed (CON). Rats were then fear conditioned with 4. tone-footshock pairings and then after 1. h and 24. h delays, given 15. tone extinction trials. Regardless of E treatment, chronic stress (VEH, E) facilitated freezing to tone during acquisition and extinction following a 1. h delay, but not during extinction after a 24. h delay. E did not influence freezing to tone during any phase of fear conditioning for either the control or chronically stressed rats, but did influence contextual conditioning that may have been carried predominately by the STR group. In the second experiment, we investigated " handling" influences on fear conditioning acquisition, given the disparate findings from the current study and previous work (Baran, Armstrong, Niren, & Conrad, 2010; Baran, Armstrong, Niren, Hanna, & Conrad, 2009). Female rats remained gonadally-intact since E did not influence tone fear conditioning. Indeed, brief daily handling (1-3. m/d/21. d) facilitated acquisition of fear conditioning in chronically stressed female rats, and either had no effect or slightly attenuated fear conditioning in controls. Thus, chronic stress impacts amygdala-mediated fear learning in both OVX- and gonadally-intact females as found previously in males, with handling significantly influencing these outcomes.

Original languageEnglish (US)
Pages (from-to)422-433
Number of pages12
JournalNeurobiology of Learning and Memory
Volume94
Issue number3
DOIs
StatePublished - Oct 2010

Fingerprint

Fear
Estradiol
Freezing
Estrogens
Learning
Sesame Oil
Conditioning (Psychology)
Prosencephalon
Amygdala
Cognition
Sprague Dawley Rats
Psychological Extinction
Handling (Psychology)

Keywords

  • Amygdala
  • Chronic stress
  • Estrogen
  • Extinction
  • Fear conditioning
  • Handling
  • Ovariectomy
  • Restraint

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Cognitive Neuroscience
  • Experimental and Cognitive Psychology

Cite this

Chronic stress, cyclic 17β-estradiol, and daily handling influences on fear conditioning in the female rat. / Hoffman, A. N.; Armstrong, Charles E.; Hanna, Jeffery J.; Conrad, Cheryl.

In: Neurobiology of Learning and Memory, Vol. 94, No. 3, 10.2010, p. 422-433.

Research output: Contribution to journalArticle

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