Corporate Banner
Satellite Banner
Scientific Community
Become a Member | Sign in
Home>News>This Article

Mice and Rats Stressed by Male Experimenters

Published: Thursday, May 01, 2014
Last Updated: Thursday, May 01, 2014
Bookmark and Share
An international team of pain researchers led by scientists at McGill University have found that the gender of the experimenters has a big impact on the stress levels of rodents.

In research published online April 28 in Nature Methods, the scientists report that the presence of male experimenters produced a stress response in mice and rats  equivalent to that caused by restraining the rodents for 15 minutes in a tube or forcing them to swim for three minutes. This stress-induced reaction made mice and rats of both sexes less sensitive to pain.

Female experimenters produced no such effects.

“Scientists whisper to each other at conferences that their rodent research subjects appear to be aware of their presence, and that this might affect the results of experiments, but this has never been directly demonstrated until now,” says Jeffrey Mogil, a psychology professor at McGill and senior author of the paper.

The research team, which included pain experts from Haverford College and the Karolinska Institutet in Sweden and a chemosensory expert from Université de Montreal, found that the effect of male experimenters on the rodents’ stress levels was due to smell. This was shown by placing cotton T shirts, worn the previous night by male or female experimenters, alongside the mice; the effects were identical to those caused by the presence of the experimenters, themselves.

Further experiments proved that the effects were caused by chemosignals, or pheromones, that men secrete from the armpit at higher concentrations than women. These chemosignals signal to rodents the presence of nearby male animals. (All mammals share the same chemosignals).

These effects are not limited to pain. The researchers found that other behavioural assays sensitive to stress were affected by male but not female experimenters or T-shirts.

“Our findings suggest that one major reason for lack of replication of animal studies is the gender of the experimenter – a factor that’s not currently stated in the methods sections of published papers,” says Robert Sorge, a psychology professor at the University of Alabama, Birmingham. Sorge led the study as a postdoctoral fellow at McGill.

The good news, Mogil says, is that “the problem is easily solved by simple changes to experimental procedures. For example, since the effect of males’ presence diminishes over time, the male experimenter can stay in the room with the animals before starting testing.  At the very least, published papers should state the gender of the experimenter who performed the behavioral testing.” 

The work was supported by grants from the Louise and Alan Edwards Foundation, the Natural Sciences and Engineering Research Council of Canada and the U.S. National Science Foundation.

 “Olfactory exposure to males, including men, causes stress and related analgesia in rodents”, Robert E. Sorge, et al.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

His and Hers Pain Circuitry in the Spinal Cord
New animal research reveals fundamental sex differences in how pain is processed.
Monday, July 06, 2015
Scientific News
High Throughput Mass Spectrometry-Based Screening Assay Trends
Dr John Comley provides an insight into HT MS-based screening with a focus on future user requirements and preferences.
Using Drug-Susceptible Parasites to Fight Drug Resistance
Researchers at the University of Georgia have developed a model for evaluating a potential new strategy in the fight against drug-resistant diseases.
Boosting Breast Cancer Treatment
To more efficiently treat breast cancer, scientists have been researching molecules that selectively bind to cancer cells and deliver a substance that can kill the tumor cells, for several years.
How Cells ‘Climb’ to Build Fruit Fly Tracheas
Mipp1 protein helps cells sprout “fingers” for gripping.
Promising Drug Combination for Advanced Prostate Cancer
A new drug combination may be effective in treating men with metastatic prostate cancer. Preliminary results of this new approach are encouraging and have led to an ongoing international study being conducted in 196 hospitals worldwide.
Non-Disease Proteins Kill Brain Cells
Scientists at the forefront of cutting-edge research into neurodegenerative diseases such as Alzheimer’s and Parkinson’s have shown that the mere presence of protein aggregates may be as important as their form and identity in inducing cell death in brain tissue.
Potential Treatment for Life-Threatening Viral Infections Revealed
The findings point to new therapies for Dengue, West Nile and Ebola.
Gut Microbes Signal to the Brain When They're Full
Don't have room for dessert? The bacteria in your gut may be telling you something.
Personalized Drug Screening for Multiple Myeloma Patients
A personalized method for testing the effectiveness of drugs that treat multiple myeloma may predict quickly and more accurately the best treatments for individual patients with the bone marrow cancer.
Nanocarriers May Carry New Hope for Brain Cancer Therapy
Berkeley lab researchers develop nanoparticles that can carry therapeutics across the brain blood barrier.

SELECTBIO Market Reports
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos