Katekoliinid

Katekoliinid, also known as catecholamines, are a group of monoamine compounds derived from the amino acid tyrosine. This group includes important neurotransmitters and hormones such as dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). They play crucial roles in the human body, mediating various physiological and psychological processes.

The synthesis of catecholamines begins in specialized cells, primarily in the brain and the adrenal medulla. Dopamine is synthesized first, and it can then be converted into norepinephrine, which in turn can be further metabolized into epinephrine. These compounds are released from nerve endings or endocrine glands into the bloodstream or synaptic cleft.

In the nervous system, catecholamines function as neurotransmitters, influencing mood, attention, arousal, and motor control. For example, dopamine is heavily involved in the brain's reward system and movement regulation. Norepinephrine plays a significant role in the "fight-or-flight" response, increasing alertness and heart rate.

As hormones, epinephrine and norepinephrine are released by the adrenal medulla during times of stress. They prepare the body for physical exertion by increasing blood flow to muscles, raising blood sugar levels, and accelerating the heart rate. The breakdown of catecholamines is primarily carried out by enzymes like monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). Dysregulation in catecholamine levels has been implicated in various neurological and psychiatric conditions, including Parkinson's disease, depression, and addiction.