Neurotransmitter changes in the brainstem and autonomic alterations during REM sleep - a mini review.

Changes of neurotransmitter levels and autonomic nervous system parameters during sleep, such as variations in blood pressure, heart and respiratory rate are well known. REM and NREM sleep stage differences are created by neurotransmitter changes mainly generated in the brainstem, but several distinct subcortical areas, such as the amygdala, hippocampus, basal ganglia or anterior insula are involved. The neurotransmitter changes differ in sleep stages and define not only the stage of sleep, but also the autonomic alterations. During NREM sleep, there is a parasympathetic dominance, while during REM sleep, the sympathetic nervous system prevails. The exact mechanism of these changes is not fully understood, the examination of neurohumoral changes caused by external stimuli and global or local networks may elucidate it. In this manuscript, we aim to provide a summary of REM sleep generation, transmitter-changes in subcortical structures and the relationship between REM sleep and the autonomic nervous system.