Kisspeptin (neurotransmitter): How It Works In The Brain
There are multiple substances and hormones that our body generates, many of which are still a mystery to science. From time to time, different hormones and proteins are found that we did not know existed or the function they had until certain research found them. And over time, these substances are investigated in greater depth and new properties of them are discovered.
This is what happened with kisspeptin a recently discovered hormone that is linked to the inhibition of metastasis and the genesis of emotions related to emotional-romantic bonding and sexual behavior.
Kisspeptin is a hormone that has been observed since puberty in the hypothalamic-pituitary-gonadal axis of both sexes, and which was discovered by a research team led by Lee in 1996 within the framework of research into cancers and their metastases. In fact, It was initially called metastin because its discovery was associated with the suppression of metastasis It would not be until 2001 that it would receive its new name, after seeing the effect that its absence has on the arrival of puberty.
The term kisspeptin actually refers to a set of different peptides derived from a common precursor to all of them and which is encoded by the Kiss1 gene.
It is a substance generated endogenously, being synthesized naturally by our body. It is secreted mainly in the hypothalamus and the hypothalamic-pituitary-gonadal axis, although it has also been discovered that this hormone is generated in large quantities in the placenta. Its operation is based on its binding to its receptor, GPR54, which is linked to the G protein (which in turn acts as a transmitter of information from a specific receptor to other proteins).
The receptors for this hormone have been found throughout the brain and nervous system, although it is possible to find a much more massive concentration in the anteroventral and arcuate nuclei of the same structure that seems to generate it, the hypothalamus. It also appears in the medulla oblongata, in the preoptic nucleus and in the medulla, being associated with the sexual response. Pancreas, adrenal cortex, liver, gonads and blood vessels are other structures in which it has been located, producing different effects.
kisspeptin has some sexual dimorphism: at the level of the anteroventral paraventricular nucleus, kisspeptin is much more present in females than in males (at least in experiments with rodents), massive exposure to androgens during pregnancy reducing the levels of this hormone and its receptors in said area.
Functions in which this substance is involved
Kisspeptin is a hormone with an important role in our body, performing different functions in different systems. Although many of them are unknown, among the best known and most researched we can find the following.
1. Awaken the libido
Kisspeptin is deeply linked to libido and sexual behavior, participating in the regulation of gonadal hormones. In fact, it has been observed that injections of this hormone generate in male mice a higher level of attraction towards females of the same species, generating a higher level of interaction between them and producing a rapprochement. In humans it has been shown that increases arousal level and attraction level that generated romantic and erotic images.
This alteration comes from the activation of the neurons in the medial posterodorsal part of the amygdala (linked to sexual appetite), as well as due to one of the main functions that have been observed at a biological level: stimulate the secretion of gonadotropin-releasing hormone In fact, the high potential that this hormone has to combat sexual dysfunctions has been raised.
This aspect has been observed mainly in men, requiring further research on the effects of kisspeptin on female sexual behavior. However, it has been observed that it causes an increase in luteinizing hormone levels (although the level of increase depends on the time of the menstrual cycle in which it is administered).
2. Promotes romance
Kisspeptin not only has a positive effect on a sexual level, but it has also been associated with an emotional component that facilitates the experimentation of romantic feelings and love as well as the detection and appreciation of this.
3. Helps regulate emotional response
Research carried out with human beings shows that after an injection of kisspeptin, not only does libido and romanticism increase, but the regulation of negative emotions is also enhanced. It facilitates relaxation and management in such a way that discomfort and stress are reduced. The possibility is raised that it could be used in pharmacological treatment of different mental disorders.
4. Reduces anxiety
Linked to the previous point, kisspeptin is also linked to a reduction in the level of anxiety, having, as we have mentioned, effects on the amygdala. This aspect has been observed in several animal models, generating behavioral relaxation and lower levels of stress. In humans, This could be associated with a decrease in anxiety in different anxiety and obsessive disorders, as well as that anxiety that causes many cases of erectile dysfunction.
5. Affects maturation and development
A relationship has been found between kisspeptin and puberty, modifying the moment in which it occurs. The administration of kisspeptin stimulates the synthesis of gonadotropin-releasing hormone and generates a early entry into puberty In women, it plays an important role in starting the menstrual cycle.
In addition to its functions in the emotional-sexual sphere, kisspeptin is a hormone really relevant in the treatment of different types of cancer And it has been observed that this hormone has a suppressive effect on the metastasis of cancers such as breast, ovary, kidney, lung and skin. In fact, the research in which this hormone was found is mainly linked to this type of application.
7. Participates in vasoconstriction
It also has an effect at the vascular level, participating in vasoconstriction and finding a certain link between kisspeptin and arteriosclerosis.
8. Contributes to the regulation of insulin levels
Kisspeptin has been found localized in the pancreas, participating in the synthesis and emission of insulin through the islets of Langerhans (in which kisspeptin can be found). There is some research that relates this hormone to diabetes.
