Darcina (pheromone): Characteristics And Effect On The Brain
Although human beings are animals, there are some biological mechanisms that occur in many species except ours, and one of them, certainly very important, is the emission of pheromones.
Pheromones can be responsible for activating very varied behaviors and physiological processes, the most important being the sexual response, and it is the pheromone known as darcina an especially important one during rodent reproduction.
This pheromone is named after an attractive character from the romantic Jane Austen, which already suggests its ability to generate a chemical attraction between animals. Let’s take a closer look at what this pheromone does and how it influences the brain of certain animals, such as rodents.
Jane Austen, famous British writer of Romanticism, introduced us to Mr. Fitzwilliam Darcy a handsome and rich young man who fell in love with the protagonist of Pride and prejudice (1813), Miss Elizabeth Bennet. Although nothing has yet been discovered in humans that can give us the power of attraction of Darcy on Lizzie, a pheromone that has a similar power has been seen in nature in rodents and has been named in honor of this romantic hero: the darcina.
Pheromones are airborne chemicals that can have varying effects on behavior in different animal species They are specific and are used as a method of communication between individuals of the same species, inducing both behavioral and physiological changes.
Although this type of substance has not been found in humans to date, in many animals pheromones are mainly responsible for the act of reproduction taking place, darcina being one of them.
Although they are small animals, with tiny brains, mice have a surprisingly complex sex life. As with other mammals, including our species, these small mammals They interpret the behavioral signals and odors emitted by other individuals of the same species as a sign that they are ready, or not, for mating It seems that darcina is a pheromone that plays a great role in this process.
When male mice urinate, in addition to marking their territory, they send a signal that they are looking for a female to mate with. Darcin is found in their urine, which will make the female mice realize the availability of the male and, depending on the smell he is emitting, go after him and decide if they want to have his offspring. This act of smelling is not as simple as in our species. Animals that use pheromones have two types of noses, each one fulfilling different functions.
On the one hand, we have the nose that performs the same function as that of humans: identifying odors. It is through this structure that animals are able to detect pleasant smells of food and go towards it or stinking smells such as that of dead animals that indicate that their meat cannot be eaten or that we are even close to danger.
But it is the vomeronasal nose, which is not found in our species, that is responsible for perceiving pheromones, such as darcina, and sending the signal to the brain. It is in the animal’s brain where the signal will be interpreted and behavior will be orchestrated according to the demands of the environment. If the hormone is reproductive, the animal will initiate behaviors in search of the individual that issued the signal that it is available for pairing, as is the case with mice.
Although the importance of darcin on the sexual behavior of mice was known, it was not until relatively recently that the brain mechanisms that would explain this type of behavior have been discovered, in addition to understanding the behavioral differences between available female mice and those who have just had babies that are still nursing.
Brain changes
A very recent study, from this year 2020 and carried out by Ebru Demir’s group at Columbia University, discovered the process by which the darcin pheromone influences the brain of female mice.
As we have already seen, it is this pheromone that activates the sexual desire of the females and makes them predisposed to mating. However, not all female mice, upon smelling the males’ urine, showed pro-mating behaviors. Females who had recently had babies and were still nursing seemed to ignore those places where males had marked their territory.
The reason behind this fact seems to be found in the medial amygdala of the rodent brain r. Ebru Demir’s group found that in this region there would be a subset of neurons, called nNOS neurons, that are activated when there is darcin floating through the air. By artificially activating this structure, the researchers saw that sexual behaviors were induced, while deactivating these neurons caused the animal to lose interest in mating.
But nNOS neurons are not simply responsible for information that has to do with darcin. These neurons are also involved in integrating sensory information about the pheromone with the internal state of the mouse, and whether it is nursing pups or not.
The main great finding of this study is that a widespread belief about pheromones has been refuted, and that is that they induce a behavioral response that is innate and immediate. In the case of darcina, it induces more complex behaviors which depend on the state of the female to whom it is directed, be it a nursing mother or a mouse in search of a male.
