Catecholamine

Catecholamines

Chemical structure of catechol, the core structure of catecholamines.

Catecholamines are a group of neurotransmitters and hormones that play a crucial role in the body's response to stress and are involved in various physiological functions. They are derived from the amino acid tyrosine and include dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline).

Biosynthesis

The biosynthesis of catecholamines begins with the amino acid tyrosine, which is hydroxylated to form L-DOPA by the enzyme tyrosine hydroxylase. L-DOPA is then decarboxylated to produce dopamine. Dopamine can be further converted into norepinephrine by the enzyme dopamine beta-hydroxylase, and norepinephrine can be methylated to form epinephrine by the enzyme phenylethanolamine N-methyltransferase.

Function

Catecholamines are involved in the "fight or flight" response, which prepares the body to respond to perceived threats. They increase heart rate, blood pressure, and blood glucose levels, and they also redirect blood flow to essential organs such as the heart and muscles.

Dopamine

Dopamine is a key neurotransmitter in the brain, involved in reward, motivation, and motor control. It is also a precursor to other catecholamines.

Norepinephrine

Norepinephrine acts as both a hormone and a neurotransmitter. It is involved in arousal and alertness and plays a role in the body's stress response.

Epinephrine

Epinephrine, also known as adrenaline, is primarily a hormone that is released from the adrenal medulla. It is crucial for the acute stress response, increasing cardiac output and raising glucose levels in the blood.

Clinical Significance

Abnormal levels of catecholamines can be associated with various medical conditions. For example, elevated levels may be found in pheochromocytoma, a tumor of the adrenal gland, while deficiencies in dopamine are linked to Parkinson's disease.

Related pages

• Neurotransmitter
• Hormone
• Adrenal gland
• Sympathetic nervous system