 Obstructive sleep apnea OSA is common and has major health implications but treatment options are limited. OSA patients show a marked reduction in upper airway UA dilator muscle activity at sleep onset and this phenomenon leads to increased collapsibility of UA compared to normal participants. Until recently, the search for medicines to activate pharyngeal muscles in sleeping humans has been discouraging. However, exciting new animal research has shown that drugs with noradrenergic and antimuscarinic effects can restore pharyngeal muscle activity to waking levels. In this protocol the investigators will test the effect of desipramine a tricyclic antidepressant with strong noradrenergic and antimuscarinic effects on genioglossus muscle activity EMG GG during sleep in healthy control participants. 