Hypocretin: characteristics and functions

Hypocretin (or orexin) It is a type of exciting neuropeptide hormone; Specifically, it is a polypeptide hormone found in the posterior hypothalamus. Its functions include inducing a feeling of hunger, stimulating a state of wakefulness or alertness, and promoting a positive mood, among others. On the other hand, presenting high levels of it has been related to sleep disorders such as insomnia or narcolepsy.

Some actions related to diet and lifestyle habits could increase the presence of this hormone. Thus, practices such as sunbathing, exercising, consuming foods with lactate, restricting glucose and increasing fructose could stimulate its secretion.

Hypocretin: what is it?

Hypocretin, also called orexin, is a type of excitatory neuropeptide hormone that was discovered in rat brains by two researchers, according to Sakurai et al. (1998) and De Lecea et al. (1998). Hypocretin, whose original name comes from the English, hypocretin, was discovered in 1998.

It is a polypeptide neuronal hormone made up of 30 amino acids. It is located in the hypothalamus, a brain structure involved in physiological functions. such as appetite, libido and sleep regulation.

Features

It was initially suggested that hypocretin was involved in the stimulation of food intake (i.e., hunger). This was believed because it was discovered that central administration of this hormone, specifically orexin-A/hypocretin-1, increased food intake.

Later, They also discovered that hypocretin stimulated insomnia, energy expenditure and wakefulness. Thus, we find different functions that this hormone exerts.

Vigil (alert state)

Hypocretin, or orexin, promotes alertness. Recent studies indicate that one of its relevant functions is to integrate the metabolic influences of circadian rhythm and sleep debtin order to determine whether an animal should be asleep or awake and active.

Specifically, hypocretin would strongly excite various brain nuclei, with important roles in insomnia (dopamine, acetylcholine, norepinephrine systems…). On the other hand, according to a study by Lin et al. (1999), a mutation of the orexin/hypocretin receptor causes canine sleep disorders, such as narcolepsy.

Eating of food

Hypocretin also has the function of stimulating or increasing the craving for food, or in other words, craving. In this sense, it interacts with substances that promote its production. Specifically, hypocretin acts by increasing its expression, being located in the arcuate nucleus of the hypothalamus.

On the other hand, some animal studies show that low orexin levels cause obesityand that this occurs even when fewer calories are consumed.

Alzheimer disease?

A study by Kang et al. (2009) linked hypocretin to Alzheimer’s disease. According to the study, the expression of the Beta-amyloid protein (a peptide that typically appears in Alzheimer’s) increases during the day and decreases at night, and all of this is controlled precisely by hypocretin.

It has been found that sleep deprivation could be the cause of the development of Beta-amyloid plaques. The same study also suggests that maintaining appropriate periods of sleep or wakefulness could prevent Alzheimer’s disease.

Influence on good mood

Hypocretin is not only related to physiological functions, but also emotional ones. So, High levels of hypocretin are related to a positive moodas well as with the feeling of happiness.

Anxiety and addictions

It is believed that low levels of hypocretin would influence the desire to smoke and drink alcohol, especially in cases of addiction. Furthermore, also Its presence has been associated with brain reward mechanisms. It has been observed how an abnormally high activity of the same leads to states of anxiety, which could make the person relapse into toxic consumption.

How to stimulate hypocretin?

Some actions or lifestyle habits can increase the presence of hypocretin in our body. Among them are:

Sunbathe: Bright lights, like sunlight, increase hypocretin levels.Do exercise: the acidification of the blood that occurs when exercising increases the excitability of hypocretin.Eat foods with lactate: lactate regulates hypocretin, while increasing our energy.Restrict glucose and increase fructose: High glucose levels can block the activity of orexin neurons.

In relation to the last thing mentioned, some foods that contain (healthy) glucose are: pasta, whole wheat bread, potatoes or legumes. On the other hand, we find foods with unhealthy glucose: white bread, salty snacks and fried foods, among others.

As we have seen, hypocretin is a hormone that is related to multiple functions, both physiological and psychological. Many have called it “the good mood hormone.”, and in this sense, it has been associated with positive emotional states. It is responsible for regulating emotions, mood and sleep/wake cycles, and is also linked to learning processes.

Finally, altered levels of it are related to sleep pathologies, obesity and even Alzheimer’s disease.

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