NORADRENERGIC PATHWAYS IN CNS

NORADRENALINE

The most prominent cluster of NA-neurons is the locus ceruleus (LC). The axons running in the discrete medial forebrain bundle (MFB), give rise the millions of NA-ergic nerve terminals throughout the cortex, hippocampus and cerebellum. The nerve terminals in this very diffuse system do not form distinct synaptic contacts, but appear to release transmitter by some distance from the target cell. Other NA-ergic neurons lie close to LC in the pons and medulla.

Axons from these cells innervate the hypothalamus, hippocampus and other parts of the forebrain, and also project to the cerebellum and spinal cord.

There are also a small number of adrenergic neurons, whose cell bodies lie more ventrally in the brainstem. Their fibers run mainly to the pons and medulla and hypothalamus, and release adrenaline rather than NA.(Fig.1).