Noradrenergic modulation of the respiratory neural network.

Noradrenergic dysregulation has been reported in human pathologies affecting the control of breathing, such as sudden infant death syndrome, congenital central hypoventilation syndrome and Rett syndrome. Noradrenergic neurons, located predominantly in pontine nuclei, are among the earliest to arise within the hindbrain and play an essential role in the maturation of the respiratory network. Noradrenergic neurons also play a major role in the modulation of the respiratory motor pattern from birth through adulthood. The critical importance of this signaling system in respiratory control is illustrated by the severe respiratory disturbances associated with gene mutations affecting noradrenergic neurons (Phox2 and Mecp2). Here, the role of catecholaminergic pontine nuclei in the control of breathing, the cellular effects of norepinephrine on the respiratory network and the pathological consequence to breathing of abnormalities in this signaling system will be discussed.