Noradrenergic control of trigeminal motoneurons in sleep: relevance to sleep apnea.

Using rapid-eye-movement (REM) sleep as a model state, we sought to determine whether noradrenaline functions to strengthen upper airway muscle tone by amplifying glutamatergic excitation on to trigeminal motoneurons. We report that noradrenaline cannot trigger motoneuron excitability on its own, instead acting to facilitate glutamatergic motor excitation.