Faculty Collaboration Database

Behavioral training interferes with the ability of gonadal hormones to increase CA1 spine synapse density in ovariectomized female rats. Eur J Neurosci 2004 Jun;19(11):3026-32

Date

06/09/2004

Pubmed ID

15182310

Pubmed Central ID

PMC1482789

DOI

10.1111/j.0953-816X.2004.03427.x

Scopus ID

2-s2.0-3042608067 (requires institutional sign-in at Scopus site)   78 Citations

Abstract

Estradiol benzoate (EB) has repeatedly been shown to increase hippocampal CA1 spine synapse density in ovariectomized female rats. Although this increase has been assumed to enhance memory, a direct link between increased spine synapse density and memory has not been demonstrated. Furthermore, while androgens, such as testosterone propionate (TP) and dihydrotestosterone (DHT), also increase spine synapse density in females, their effects on memory have yet to be investigated. In the present study, ovariectomized female rats were given two injections, 24 h apart, of sesame oil (control), 10 microg EB, 500 microg TP or 500 microg DHT. Forty-eight hours after the second injection, rats were tested in a 1-day spatial Morris water maze task and then immediately perfused for analysis of CA1 spine synapse density (using electron microscopy and unbiased stereology). In the spatial acquisition phase of testing, EB, but not TP or DHT, significantly impaired memory relative to controls. Hormone treatment did not affect spatial retention or performance in the non-spatial phase of testing. In contrast to previous work, spine synapse density was not increased by EB, TP or DHT. We therefore examined a new set of EB-treated females, only half of which were water maze tested. Consistent with previous work, EB significantly increased spine synapse density among behaviorally naïve females. In contrast, spine synapse densities did not differ among behaviorally tested control and EB females, although they were higher than behaviorally naïve controls. These data indicate that 1-day water maze testing can eliminate the hormone-induced increases in CA1 spine synapse density typically observed in behaviorally naïve females.

Author List

Frick KM, Fernandez SM, Bennett JC, Prange-Kiel J, MacLusky NJ, Leranth C

Author

Karyn Frick BA,MA,PhD Professor in the Psychology department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Analysis of Variance
Animals
Behavior, Animal
Cues
Female
Gonadal Hormones
Hippocampus
Maze Learning
Microscopy, Electron
Ovariectomy
Rats
Rats, Sprague-Dawley
Spatial Behavior
Swimming
Synapses