REM Sleep-active Pedunculopontine Tegmental Neurons Supresses REM Sleep Expression and Respiratory Network Activity

• Main Author: Grace, Kevin
• Other Authors: Horner, Richard
• Language: en_ca
• Published: 2010
• Subjects: REM sleep; Pedunculopontine Tegmental Nucleus; Breathing; 5HT1A Receptor; 0317; 0719
• Online Access: http://hdl.handle.net/1807/25603

The mechanisms underlying the generation of rapid eye movement (REM) sleep are poorly understood. Despite a lack of direct support, neurons maximally active during REM sleep (REM sleep-active) located in the pedunculopontine tegmental nucleus (PPTn) are hypothesized to generate this state and its component phenomenology. This hypothesis has never been directly tested, since the results of selectively inhibiting this cell-group have never been determined. Using microdialysis, electrophysiology, histochemical and pharmacological methods in freely-behaving rats (n=22) instrumented for sleep-wake state and respiratory muscle recordings, I selectively inhibited REM sleep-active PPTn neurons. Contrary to the prevailing hypothesis, I showed that REM sleep-active PPTn neurons suppress REM sleep by limiting the frequency of its onset. These neurons also shape the impact of REM sleep on breathing. REM sleep-active PPTn neurons restrain behavioural activation of upper-airway musculature during REM sleep, while depressing breathing rate and respiratory activation of the upper-airway musculature across sleep-wake-states.