"Kissing hormone": new data
The same substance stimulates sexual activity and reduces anxiety
Ksenia Malysheva, N+1
Stimulation of neurons with kisspeptin protein receptors in mice led to a decrease in anxiety and more active communication with females. Perhaps the deactivation of these neurons can switch the interest of males to other males.
Protein with the memorable name "kisspeptin" it is encoded by the KISS1 gene. It plays an important role in the production of gonadoliberin, a hormone that regulates puberty. It is known that with artificially increased concentration of kisspeptin in the brain, mice begin to communicate more actively with the opposite sex. However, both the protein and the gene got their name not for their role in regulating sexual behavior, as one might think in consonance with the English word kiss – "kiss", but from the Hershley Kiss candy brand, because they opened it near a chocolate factory. Biologist Danny Welsh and his colleagues were not looking for a gonadoliberin precursor at all, but a cure for cancer.
A new study presented last week at the British Endocrinological Society conference sheds light on the previously unknown functions of kisspeptin. It turned out that, in addition to puberty and sexual behavior, the protein regulates social behavior in a broader sense, and also reduces anxiety, at least in mice.
A population of neurons with kisspeptin receptors was previously found in the amygdala, a part of the brain that is involved in the formation of emotions and social behavior. In animals that respond to pheromones – chemical signals that stimulate sexual behavior (according to available data, humans do not belong to such animals), kisspeptin participates in cascades of reactions that are triggered by pheromones; a significant part of such reactions occurs in the amygdala.
An international group of neuroscientists led by Daniel Adekunbi pointwise stimulated kisspeptin receptors in the brains of male mice and observed how stimulation affects their sexual and social behavior. It turned out that the activation of neurons sensitive to kisspeptin causes males to show increased interest in females and generally makes them more sociable. Standard tests for the level of anxiety showed that the increased activity of kisspeptin neurons also significantly reduces the level of anxiety in animals; animals reacted less strongly to stimuli.
Scientists have concluded that amygdala neurons with kisspeptin receptors coordinate behavior, increasing the chances of a male to leave offspring; under their influence, animals become calmer and more willing to have sexual contact. In the future, the researchers plan to find out how the behavior of males changes with the artificial deactivation of kisspeptin-sensitive neurons. In addition, the experiments will be repeated with female rodents.
The experiments were conducted on mice, but the authors believe that neurochemical reactions involving kisspeptin may play a similar role in the formation of human sexual behavior. If this assumption is confirmed, kisspeptin receptors may become the target of new drugs for sexual dysfunction in men, and possibly women.
The authors also cautiously suggest that kisspeptin may be involved in the formation of sexual preferences, at least in mice. "It would be interesting to find out whether the deactivation of kisspeptin receptors will lead to the fact that males will prefer other males to females," says Adekunbi.
The results of the work of the Adekunbi group and the theses of the report are presented on the EurekAlert portal! (Kisspeptin boosts male sexual appetite and reduces anxiety).
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