<P> Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction in the skin and gastrointestinal tract, smooth muscle (bronchiole and capillary) dilation, and increased metabolism, all of which are characteristic of the fight - or - flight response . Release of catecholamines is stimulated by nerve impulses, and receptors for catecholamines are widely distributed throughout the body . </P> <P> Neoplasms include: </P> <Ul> <Li> Pheochromocytoma (most common), a catecholamine - secreting tumor of the adrenal medulla </Li> <Li> Neuroblastoma, a neuroendocrine tumor of any neural crest tissue of the sympathetic nervous system </Li> <Li> Ganglioneuroma, a tumor in the nerve cells of the peripheral nervous system </Li> </Ul> <Li> Pheochromocytoma (most common), a catecholamine - secreting tumor of the adrenal medulla </Li>

Initiates the release of norepinephrine/epinephrine from the suprarenal medulla