Figure 9.

Schematic illustration shows the possible relationship of NA-mediated neuroprotective mechanism during sleep and waking. During waking as the brain is metabolically more active, more ROS is generated; however, continuous release of NA from the NA-ergic REM-OFF neurons protects the brain from oxidative damage. NA prevents ROS generation in cells by reducing α1-AR mediated reduction in LP as well as by possible chelation of Fe²⁺ (A). Further during REMS, NA-ergic REM-OFF neurons slow-down and stop activity resulting in washing-off the accumulated NA to maintain homeostasis and the cycle repeats (B). Thus, the finding helps explaining role of REMS in maintaining brain NA level. Abbreviations are as in the text.