Study suggests stress of task determines if estrogen helps cognition

August 27, 2004

CHAMPAIGN, Ill. -- Does estrogen help cognition? Many women ponder that question as a quality-of-life issue while deciding on estrogen therapy since it has been linked to potential disease complications. Now, a new study at the University of Illinois at Urbana-Champaign suggests that the stress of any given task at least partially determines if hormones will help the mind.

Reporting in the August issue of Behavioral Neuroscience, four researchers show the introduction of a single stressor -- water temperature -- into a water maze prompted opposite responses among female rats with either high or low levels of estrogen and progesterone.

"Water temperature totally reversed who did better," said Janice M. Juraska, a professor of psychology and of neuroscience. "Proestrous rats, which have high hormone levels, did better when the water was warm, presumably because they were less stressed. Estrous rats did better when the water was cold, presumably because they are not as prone to get stressed during this time."

Proestrous rats are fertile and ready to mate, while estrous rats have low hormone levels and won't mate. For the study -- funded by a grant to Juraska from the National Science Foundation -- 44 female rats were divided into four groups. The two groups of rats in proestrus and the two groups in estrus had to learn the route and swim to a submerged platform in either warm (91 degrees Fahrenheit; 33 Celsius) or cold water (66.2 degrees Fahrenheit; 19 Celsius).

Many scientists have tried to answer the hormones-cognition question, but the various findings, measuring different tasks, have been inconsistent and often contradictory.

"These discrepancies of sometimes opposite results have been very difficult to resolve," Juraska said. "Even for simple tests of spatial behavior, high hormones can either help or hinder, and nobody has understood why."

Juraska's lab previously had shown in studies using the water maze that rats with high levels of hormones, either naturally occurring in the estrous cycle or with high doses administered into rats whose ovaries had been removed, do less well finding the platform.

Psychology doctoral student Marisa J. Rubinow, a co-author of the new study, wondered if stress during a task might be a factor in the varied results showing up in the literature. Now, after the new results, Rubinow and Juraska suggest that the timing and duration of stress, as well as the memory systems involved in a task, all may be factors that determine the effects of ovarian hormones on performance.

"Will hormones help how your brain works -- how you think, your cognition?" Juraska said. "I wish I had a simple answer. It depends on many things about the task, and one of them is how stressful the task is. There is no simple translation to behavior."
-end-
Other co-authors on the paper were Linda M. Arseneau, formerly in the department of animal sciences and now with the U. of I. Division of Research Safety, and J. Lee Beverly, a professor of animal sciences and of neuroscience.

University of Illinois at Urbana-Champaign

Related Stress Articles from Brightsurf:

Stress-free gel
Researchers at The University of Tokyo studied a new mechanism of gelation using colloidal particles.

Early life stress is associated with youth-onset depression for some types of stress but not others
Examining the association between eight different types of early life stress (ELS) and youth-onset depression, a study in JAACAP, published by Elsevier, reports that individuals exposed to ELS were more likely to develop a major depressive disorder (MDD) in childhood or adolescence than individuals who had not been exposed to ELS.

Red light for stress
Researchers from the Institute of Industrial Science at The University of Tokyo have created a biphasic luminescent material that changes color when exposed to mechanical stress.

How do our cells respond to stress?
Molecular biologists reverse-engineer a complex cellular structure that is associated with neurodegenerative diseases such as ALS

How stress remodels the brain
Stress restructures the brain by halting the production of crucial ion channel proteins, according to research in mice recently published in JNeurosci.

Why stress doesn't always cause depression
Rats susceptible to anhedonia, a core symptom of depression, possess more serotonin neurons after being exposed to chronic stress, but the effect can be reversed through amygdala activation, according to new research in JNeurosci.

How plants handle stress
Plants get stressed too. Drought or too much salt disrupt their physiology.

Stress in the powerhouse of the cell
University of Freiburg researchers discover a new principle -- how cells protect themselves from mitochondrial defects.

Measuring stress around cells
Tissues and organs in the human body are shaped through forces generated by cells, that push and pull, to ''sculpt'' biological structures.

Cellular stress at the movies
For the first time, biological imaging experts have used a custom fluorescence microscope and a novel antibody tagging tool to watch living cells undergoing stress.

Read More: Stress News and Stress Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.