FARBE FIRMA

Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone and neurotransmitter. The name "noradrenaline", derived from Latin roots meaning "at/alongside the kidneys", is more commonly used in the United Kingdom; in the United States, "norepinephrine," derived from Greek roots having that same meaning, is usually preferred.^[1]"Norepinephrine" is also the international nonproprietary name given to the drug.^[2] Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic.

In the brain, norepinephrine is produced in nuclei that are small yet exert powerful effects on other brain areas. The most important of these nuclei is the locus coeruleus, located in the pons. Outside the brain, norepinephrine is used as a neurotransmitter by sympathetic ganglia located near the spinal cord or in the abdomen, and it is also released directly into the bloodstream by the adrenal glands. Regardless of how and where it is released, norepinephrine acts on target cells by binding to and activating noradrenergic receptors located on the cell surface.

The general function of norepinephrine is to mobilize the brain and body for action. Norepinephrine release is lowest during sleep, rises during wakefulness, and reaches much higher levels during situations of stress or danger, in the so-called fight-or-flight response. In the brain, norepinephrine increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention; it also increases restlessness and anxiety. In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.