Catecholamines - Norepinephrine
Norepinephrine pathways originate in the brain stem and send projections to the cerebral cortex, hypothalamus, limbic system, and the cerebellum. There are a large number of receptor types fornorepinephrine. The two main classes are alpha and beta. Activation of these receptors usually leads to excitation of the cell, but one of the subclasses of these receptors, when activated, is inhibitory. Some of the antidepressants will function by modulating (enhancing) the norepinephrine system.