Adrenergic mechanisms

The adrenergic or sympathetic nervous system is part of the autonomic nervous system and comprises neural and endocrine circuits that use norepinephrine or epinephrine as neurotransmitters. The adrenergic system includes norepinephrine- and epinephrine-producing neurons in the central nervous system, norepinephrine-producing postganglionic sympathetic neurons, and epinephrine-producing cells of the adrenal medulla. These systems play critical roles in mechanisms coordinating homeostatic responses to environmentally and systemically generated challenges. Disturbances in their function (either reduced or increased activity) cause symptomatic disease.