Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chronic exposure to estradiol impairs some cognitive functions

01.08.2008
University of Illinois researchers report this week that chronic exposure to estradiol, the main estrogen in the body, diminishes some cognitive functions.
Rats exposed to a steady dose of estradiol were impaired on tasks involving working memory and response inhibition, the researchers found.

Their report appears this week in the journal Behavioral Neurosciences.

The researchers made the discovery when studying the effects of estradiol on activities mediated by the prefrontal cortex, a brain region that is vital to working memory and to the ability to plan, respond to changing conditions and moderate or control one’s behavior.

... more about:
»Estrogen »Schantz »cognitive »estradiol

Working memory is the ability to briefly remember information needed for a particular task, said Susan Schantz, a U. of I. professor of veterinary biosciences and principal investigator on the study. An example in humans is a phone number that is forgotten soon after the number is dialed.

“With working memory you’re just keeping it active until you use it,” she said.

In the new study, rats were trained to press one of two levers to obtain a food reward. Those that alternated between the levers (which were withdrawn from the rat enclosure for a few seconds between trials) received a reward. Those that hit the same lever twice in a row got no reward. Rats exposed to estradiol performed worse than their counterparts on this task, earning significantly fewer rewards.

A second set of tests measured the rats’ ability to wait before responding to a stimulus. The rats had to wait 15 seconds before pushing a lever to get a reward. Those exposed to estradiol performed worse on this task than those that were not exposed.

“That’s the test where we really saw the most striking effects with estradiol,” Schantz said. The estradiol-treated rats “were not as good at waiting,” she said.

“Rats treated with estradiol are definitely a lot more active and make a lot more lever presses,” said neuroscience graduate student Victor Wang, the lead author on the study. “That’s not conducive toward being rewarded.”

The researchers had not expected to see such pronounced results. In fact, the study had been designed to give them baseline information for a separate inquiry into the effects of soybean estrogens on cognitive function. They planned to compare the effects of chronic estradiol exposure to the effects of chronic exposure to genistein, a phytoestrogen found in soybeans. Genistein is believed to have similar effects in the body as natural or synthetic estrogens, although no study has definitively proven that it does.

Schantz and her colleagues had focused on the prefrontal cortex because it is rich in estrogen receptor beta (ER-beta), a protein that spurs gene expression and other activities in the cell when it binds to estradiol. Genistein also activates ER-beta.

Some women take genistein supplements or eat soy-based foods to reduce hot flashes or other symptoms of menopause, Schantz said.

“Women take them thinking they’ll be a safe alternative to hormone-replacement therapy and they might help hot flashes,” she said. Those who have heard that hormone replacement can improve cardiac or brain function also hope that eating soy or taking genistein supplements will have the same effects, she said.

The effects of hormone replacement therapy (HRT) are more complex – and problematic – than once thought. A recent large-scale study of HRT in post-menopausal women was stopped because of an increased risk of stroke and blood clots in women taking estrogen alone, and a higher than average incidence of breast cancer, cardiovascular disease, blood clots and stroke in women taking estrogen and progesterone.

Studies of estrogen’s effects on cognition have also had mixed results. In earlier studies, for example, psychology professor Donna Korol, a collaborator on the current project, found that estradiol enhances some abilities, such as place or spatial learning, while hindering others, such as learning that relies on stimulus-response associations, considered by some to be akin to “habit” and not fluid thought.

Performance in these tasks involves brain structures outside the prefrontal cortex.

The research indicates that multiple factors influence the effects of estradiol on the brain, Schantz said. The timing of the exposure, the types of brain functions or structures studied and the age of the test subjects can all generate different results, she said.

Diana Yates | University of Illinois
Further information:
http://www.illinois.edu

Further reports about: Estrogen Schantz cognitive estradiol

More articles from Life Sciences:

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
21.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
21.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>