TITLE:
Effects of 17β-Estradiol on Cognitive Performance of Ovariectomized Female Rats Exposed to Space Radiation
AUTHORS:
Bernard M. Rabin, Kirsty L. Carrihill-Knoll, Lauren V. Long, Steven C. Pitts, Barbara Shukitt Hale
KEYWORDS:
Cosmic Rays; Behavior; Sex Differences; Estrogen
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.3 No.1,
February
27,
2013
ABSTRACT: On exploratory class missions to other planets astronauts will be
exposed to types and doses of radiation that are not experienced in low earth
orbit. While it is likely that the crew will consist of both male and female
astronauts, there has been little research on the effects of exposure to space
radiation on central nervous system function and cognitive performance
in female subjects. Because estrogen can function as a neuroprotectant, the
present experiments were designed to evaluate whether or not the presence
or absence of estrogen at the time of irradiation would affect the susceptibility
to the neurocognitive effects of exposure to 56Fe particles in
female rats. Capsules containing 17β-estradiol
or vehicle were implanted in ovariectomized rats three days prior to exposure 56Fe
particles (50 - 200 cGy, 1000 MeV/n). Cognitive performance was evaluated using
novel object recognition memory to measure learning and memory and operant
responding on an ascending fixed-ratio schedule to measure changes in
motivation and in the responsiveness to environmental contingencies. The
results indicated the estrogen does not function as a neuroprotectant to minimize
the cognitive effects of exposure to 56Fe particles. However, the
presence/absence of estrogen at the time of irradiation could modulate the
responsiveness of the subject to the disruptive effects of exposure to HZE
particles on the performance of specific cognitive tasks.