Main point: Researchers have found a peptide/a neurotransmitter, the release of which greatly increases in happiness and decreases in sadness.
Journal: Nature Communications
The name of the peptide is hypocretin that can increase both mood and alertness in humans. According to experts, this chemical can become the basis of treating the psychiatric disorders such as depression.
Researchers also worked on another chemical, a peptide called as melanin concentrating hormone (MCH), the release of which is less in waking state while very large during sleep.
“The current findings explain the sleepiness of narcolepsy, as well as the depression that frequently accompanies this disorder,” Jerome Siegel, M.D., senior author, said in a statement. “The findings also suggest that hypocretin deficiency may underlie depression from other causes.”
In this study, researchers worked on eight patients, who were being treated at Ronald Reagan UCLA Medical Center for intractable epilepsy. Researchers used the intracranial depth electrodes to work on the brain areas along with the membrane like that used for kidney dialysis. They used a very perceptive radioimmunoassay process to find the release of hypocretin and MCH in amygdala. They also asked the participants to fill moods and attitudes questionnaire every hour of wakefulness.
Researchers found that hypocretin levels increase during positive emotions, anger, social interactions and awakening while MCH levels were highest during sleep onset and after eating, and lessened during social interactions. Both of these chemicals are at low levels during postoperative pain.
“Melanin-concentrating hormone levels increase at sleep onset, consistent with a role in sleep induction, whereas hypocretin-1 levels increase at wake onset, consistent with a role in wake induction.” Researchers noted.
“These results suggest a previously unappreciated emotional specificity in the activation of arousal and sleep in humans,” Siegel said. “The findings suggest that abnormalities in the pattern of activation of these systems may contribute to a number of psychiatric disorders.”
Blouin, A., Fried, I., Wilson, C., Staba, R., Behnke, E., Lam, H., Maidment, N., Karlsson, K., Lapierre, J., & Siegel, J. (2013). Human hypocretin and melanin-concentrating hormone levels are linked to emotion and social interaction Nature Communications, 4 DOI: 10.1038/ncomms2461