Nitric oxide (NO) and obstructive sleep apnea (OSA).

Nitric oxide (NO) and obstructive sleep apnea are inseparable. Obstructive sleep apnea could be described as the intermittent failure to transport the full complement of nasal NO to the lung with each breath. There NO matches perfusion to ventilation. NO is utilized by the efferent pathways that control the unequal, inspiratory battle between the pharyngeal dilators and the closing negative pressures induced by the thoracic musculature. Recurrent cortical arousals are a major short-term complication, and the return to sleep after each arousal uses NO. The long-term complications, namely hypertension, myocardial infarction, and stroke, might be due to the repeated temporary dearth of NO in the tissues, secondary to a lack of oxygen, one of NO's two essential substrates.