Catecholamines are a group of chemicals that act as neurotransmitters and hormones in the body.
The principal ones include epinephrine, norepinephrine, and dopamine. They are produced in the brain, the sympathetic component of the autonomic nervous system, and in the adrenal medulla and other sympathochromaffin tissues. Sympathochromaffin tissues are neuroendocrine tissues that are associated with the sympathetic nervous system and are located in groups along the major central arteries of the body and can be found from the base of the brain to the pelvis.
These substances are responsible for a multitude of nervous system and stress responses. They regulate blood pressure, heart rate, the flight or fight reactions to stress, metabolism, mood, pleasure, and more.
Epinephrine is produced in and released by the adrenal medulla in response to sympathetic activation. It is actually made from norepinephrine by an enzyme (phenylethylenolamine N-methyl transferase) that is regulated by cortisol. It is the main hormone that accounts for the chemistry of the fight or flight response. People who have had their adrenal glands removed still have normal stress responses because norepinephrine takes the place of epinephrine in most situations.
There are a lot of drugs that act like catecholamines and others that block the effects of catecholamines.
Excess catecholamine production can occur in the setting of a tumor of the adrenal medulla known as a pheochromocytoma and also in some children with tumors of the adrenal medulla know as neuroblastoma. Sympathetic parganglioma, most often in the abdomen, can also release excess catecholamines. Symptoms most often include spells of tachycardia, hypertension, labile hypertension, anxiousness, and an impending sense of doom. Some people have persistent hypertension and others may have diabetes mellitus. Not all have the spells. These tumors will be discussed in detail in later articles.
Disorders leading to dysfunction of the autonomic system can result in symptoms and signs such as low blood pressure, drops in blood pressure when standing and other usual symptom patterns.
They are not considered adrenal disorders.
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