Elevation of brain serotonin during dying.

Death and dying are central events in the live of an organism, but neurobiological changes during this process are still rarely understood. Extracellular levels of serotonin, one of the phylogenetically oldest neurotransmitters, were measured continuously during dying. Serotonin levels increased threefold, while the EEG recorded simultaneously went down to a zero-line of no activity. This could be caused by the neuroprotective activity of brain serotonergic system, which subjectively makes dying easier due to the mood enhancing function of this neurotransmitter.