A group of steroids found in female mouse urine goes straight to the male mouse's head, according to researchers at Washington University School of Medicine in St. Louis. They found the compounds activate nerve cells in the male mouse's nose with unprecedented effectiveness.
"These particular steroids, known as glucocorticoids (GCCs), are involved in energy metabolism, stress and immune function," says senior author Timothy E. Holy, Ph.D., assistant professor of neurobiology and anatomy. "They control many important aspects of the mouse's physiology and theoretically could give any mouse that sniffs them a detailed insider's view of the health of the animal they came from."
Holy plans further research to see if activating the nerves in the male mouse's nose leads to particular behavioral responses. He probes the male mouse's reaction to chemical signals from female mice to advance understanding of pattern recognition and learning in the much more complex human brain. In 2005, he found that female mice or their odors cause male mice to sing. He doesn't know yet if the GCC steroids' effects on the male mouse nose help to trigger this behavior.
Science has long recognized that urine, sweat and other bodily fluids contain chemical communication signals called pheromones that can influence the biology or behavior of others. Most mammals use the information in these signals for social purposes, such as establishing territory or dominance, or in courtship and mating. In many cases, though, the specific chemical identities of the signals are unknown.
The new study, published in The Journal of Neuroscience and led by graduate student Francesco Nodari, identified compounds that are unusually potent stimulators of the mouse nose. The pheromones activate nerve cells 30 times as often as all the other pheromones previously identified in female mouse urine combined. In addition, several of the new signals activate specific nerve cells. This may mean the male mouse's brain can assess different aspects of female mouse health by selectively analyzing individual pheromones.
Stressing female mice led to a threefold increase in the levels of GCCs in their urine, directly linking the female mouse's health and the GCC pheromones.
The GCC pheromones that Nodari identified were sulfated, which means they had a chemical attachment comprised of sulfur and oxygen atoms. This attachment is added to deactivate the steroids prior to excretion in the urine. When Nodari used an enzyme to remove these attachments, the GCCs lost their ability to activate nerves, further suggesting that the link between the sulfated GCCs and the nerve cells is a channel fine-tuned by evolution to carry information from female mice to male mice.
The nerves researchers studied in the male mouse nose are located in an area known as the accessory olfactory system. Humans and many closely related apes don't have an accessory olfactory system, but most other mammals and some reptiles do. The system, found in a structure called the vomeronasal organ, sends its outputs to a different part of the brain than the main olfactory system. Like the main olfactory system, it's dedicated to detecting airborne particles. But researchers believe the accessory olfactory system focuses on compounds from sources that are physically very close to or touching the animal.
According to Holy, this focus on scents from nearby sources makes the accessory olfactory system "halfway between a taste system and a sense of smell." He believes the GCC pheromones account for approximately 75 percent of the signals detected in female urine by the male accessory olfactory system.
"Because these new pheromones are so good at activating the accessory olfactory system, they will be very helpful in efforts to better understand what this system does," he says. "That high degree of activation likely also means they have much potential for advancing the general study of pheromones."
To follow up, Holy's lab is testing to see how mice change their behavior when they smell these compounds. They are also searching for additional pheromonal cues that the accessory olfactory system can detect in female urine.
Nodari F, Hsu F-F, Fu X, Holekamp TF, Kao L-F, Turk J, Holy TE. Sulfated steroids as natural ligands of mouse pheromone-sensing neurons. The Journal of Neuroscience, June 18, 2008.
Funding from the United States Public Health Service supported this research.
Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked third in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
Michael C. Purdy | EurekAlert!
Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Chemists at FAU successfully demonstrate imine hydrogenation with inexpensive main group metal
22.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
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...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
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...
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...
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...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology