Mouse tears
In the tears of the mice, they found a built-in protection against pedophilia
The tears of mice contain the peptide ESP22, which plays the role of an anti-pheromone and signals to adult males that the animal is not yet ready for reproductive activity. Details with reference to an article by researchers from the USA and Japan in the journal Nature.
Obviously, the last phrase refers to "The article by Ferrero et al. A juvenile mouse pheromone inhibits sexual behavior through the vomeronasal system is published in the journal Nature; a popular summary can be read in the Harvard Medical School press release: Tears for fears. Juvenile mice secret a protective pheromone in their tears, blocking adult mating" – VM.
The role of the identified peptide in regulating sexual behavior was proved in a series of experiments that began with a continuous search for all pheromones and similar substances in mice of different genders and ages. Using the polymerase chain reaction method, biologists searched for RNA molecules on the basis of which certain peptides are synthesized and as a result they managed to find several short protein chains that were found only in immature individuals. A peptide designated as ESP22 attracted particular attention.
Scientists isolated this substance from the lacrimal fluid of mice of several ages and found that its maximum concentration is observed in animals aged two to three weeks, and by one month (the minimum age of puberty in mice) ESP22 becomes significantly less. Further, biologists found out that the studied peptide causes specific electrical activity of olfactory cells, so it can really be perceived by the sense of smell of other mice. In addition, scientists were able to identify the protein receptor responsible for the perception of the smell of the peptide and used this information (we are talking about the TRPC2 protein) in further experiments.
But first, the researchers identified neurons in the limbic system that were activated by olfactory cells that encountered the smell of ESP22. Immunohistochemical analysis showed that after presenting an adult animal with a substance isolated from the tears of mice, some brain cells synthesize the c-Fos protein, which is usually synthesized in neurons involved in the information processing process. These data showed that the peptide not only has a smell, but also somehow affects the brain of rodents.
To find out what the ESP22 smell tells animals, scientists using genetic engineering obtained genetically modified mice without the TRPC2 protein. This change, as it followed from previous experiments on the search for olfactory receptors, made rodents insensitive to the peptide and as a result, biologists discovered "pedophile mice": males deprived of TRPC2 receptors stubbornly tried to mate even with immature mice of both sexes, to which ordinary adult mice showed little interest. Mutants, equally with other mice, attempted to climb on adult females in a state of estrus, but lost the ability to distinguish them from mice, despite the obvious difference in size.
Applying ESP22 to young mice in excess of the usual concentration led to the fact that rare attempts by adult males (normal, and not the mutants described above) became even more rare. All the collected data, as the researchers write, strongly suggest that ESP22 really blocks the sexual attraction of adult males to immature individuals and thus allows them to protect the latter from dangerous relationships, while minimizing the costs of males for obviously meaningless attempts at fertilization.
Scientists urge to refrain from transferring the data of their research to humans, since the sense of smell plays a much more important role in the life of rodents than in the lives of humans. The olfactory system of rodents is arranged completely differently, and reliable data on the more or less serious role of pheromones in humans has not yet been obtained.
Portal "Eternal youth" http://vechnayamolodost.ru03.10.2013