A fascinating research project undertaken by Jeff Mogil’s lab at McGill University, and covered nicely in an April 28 news article in Science, suggests that the odors emanating from male laboratory technicians elevate the stress level of mice, causing the rodents, paradoxically, to feel less pain.

The study rose out of observations that Mogil’s students could not explain: When rodents were tested for pain responses, some seemed oblivious. Looking further, the students determined that the mice that didn’t feel pain had been handled by male technicians. Turns out that rodents exposed to male odors were actually feeling less pain, rather than simply hiding the pain they were in, the Science article notes. The male aroma ramped up their stress levels, which deadened the hurt.

This isn’t just an academic exercise. Animal models, rodent models in particular, are essential to research. Mogil, who has studied pain for 25 years, has been looking at a number of innovative approaches to measure spontaneous pain, either directly or indirectly, in animals (see Sept. 23, 2013 Eureka blog.)  Mogil suggests that that their recent discovery tying male scent to rodent behavior could possibly explain why some laboratories might have difficulty reproducing results from previous experiments. Here is a link to the olfactory study by Mogil’s lab, which appeared online this week in the journal Nature Methods.