How is Neurotransmitter Hypocretin linked to Happiness?

Researchers discovered that the peptide tied to the neurotransmitter hypocretin increased in people when they were happy and decreased when they were sad. This is related to increased alertness and mood in humans. The groundbreaking discovery gives direction for future research on the potential treatment of depression and similar disorders affecting mood. Hypocretin deficiency can distinguish the underlying cause of depression from other causes.

Another measurement was done of the release of the peptide related to melanin concentrating hormone (MCH). The release of this peptide increases during sleep and is limited when awake. This explains the relationship between sleepiness of those suffering from narcolepsy and depression. Those with narcolepsy had fewer hypocretin nerve cells in the brain compared to a control group.

The strong association between depression and narcolepsy explains the link of hypocretin in the manifestation of mood disorders.

Researchers collected hyocretin and MCH data from the brains of eight people being treated for intractable epilepsy. They were given brain implantation of intracranial depth electrodes in order to identify the area of the brain where seizures originate. Researchers measured the release of hypocretin and MCH using a radioimmunoassay procedure and had patients record their moods on a questionnaire. The procedure was to allow patients to watch television, engage in social interactions, and experience transitions between sleep and wakefulness.It was discovered that hypocretin levels are not linked to arousal in general, but had its effect during positive emotions, anger, social interaction and awakening. MCH levels were highest during sleep and minimal during social interaction.

Hypocretin elevates mood and alertness in humans. This suggests that the abnormalities of the pattern of activation between MCH and hypocretin have a significant contribution to mood disorders.

Source: http://psychcentral.com/news/2013/03/09/researchers-find-link-between-peptide-and-happiness/52387.html