Protein hypocretin – the key to feeling happy?
Experts know almost nothing about the neurochemical changes underlying human emotions and social behavior. In their latest work, researchers at the University of California at Los Angeles, working under the guidance of Professor Jerome Siegel, demonstrated for the first time that people who are in a state of happiness have an increased release of the neurotransmitter hypocretin, which decreases in a state of sadness.
In addition, they found that the production of another peptide – melanin–concentrating hormone - is minimal during walking and maximal during sleep. This indicates a key role belonging to this peptide in the occurrence of drowsiness.
In 2000, Siegel and his colleagues published data according to which the brains of people suffering from narcolepsy – a neurological disorder characterized by uncontrolled periods of deep sleep – contain 95% fewer hypocretin neurons than in the brains of healthy people. This study for the first time pointed to a potential biological cause of the development of this disease.
Given that there is a pronounced relationship between depression and narcolepsy, researchers have studied hypocretin and its possible involvement in the mechanisms of depression.
As part of their latest work, they analyzed data obtained when working with eight patients undergoing treatment at the university medical center for persistent epilepsy. In order to identify convulsive foci for subsequent surgical intervention, intracranial electrodes were implanted in them. With the consent of the patients, the authors used the same electrodes to obtain data on the intensity of release of hypocretin and melanin-concentrating hormone.
The indicators necessary for scientists were recorded while patients watched TV, engaged in social contacts, such as communication with the attending physician, medical staff and visiting family members, ate, underwent various medical manipulations, as well as during falling asleep and waking up. Every 15 minutes, simultaneously with taking a sample for microdialysis, patients recorded the nature of their pastime. Every hour while awake, they assessed their mood and disposition by filling out a special questionnaire.
Analysis of the collected data showed that the level of hypocretin is not associated with the state of arousal in general, but it rises to maximum values during periods when a person experiences positive emotions or anger, enters into social contacts or wakes up from sleep. Levels of melanin-concentrating hormone, on the contrary, are maximal during falling asleep and minimal during communication with other people.
Siegel notes that hypocretin antagonists are currently being developed by several pharmaceutical companies as drugs for the treatment of insomnia. The data obtained indicate that such medicines will not only contribute to falling asleep, but also negatively affect a person's mood. At the same time, stimulation of hypocretin production, which can improve mood and increase mindfulness, is a potential therapeutic approach to the treatment of psychiatric disorders such as depression.
Article by Ashley M. Blouin et al. Human hypocretin and melanin-concentrating hormone levels are linked to emotion and social interaction published in the journal Nature Communications.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on UCLA materials: Is this peptide a key to happiness?
11.03.2013