What Are the Functions of Norepinephrine?

Playing multiple key roles in several of the human body's major systems, norepinephrine is among the most significant of the neurotransmitters comprising the amino acid group and is categorized as a functional hormone. Originating from the locus ceruleus in the brain stem, the adrenal medulla, as well as the postganglionic neurons within the sympathetic nervous system, norepinephrine can trigger a range of complex reactions and effects. Frequently also referred to as noradrenaline, the substance characteristically is released in the midst of a physically or mentally taxing or stressful occurrence. Production of norepinephrine affects the operation of the human nervous system, vascular functions, liver processes and mood regulation. Useful not only during times of natural, internal release, noradrenaline also is commonly used medicinally to treat a range of disorders and conditions.

The interaction of norepinephrine and the nervous system is evidenced by its support of the fight-or-flight instinct and its boosting of mental acuity, alertness and attentiveness in times of stress or danger. This interaction with the central nervous system produces the frenetic responses that often accompany threatening or hazardous circumstances. The substance is not produced indefinitely, but only for as long as is necessary to respond to the crisis at hand. Overproduction of norepinephrine by the adrenal medulla can result in cessation of physiological functions, including digestion, and is therefore kept in check by the release of balancing amounts of cortisol.

When functioning as a hormone, this important neurotransmitter has the ability to alter the operation of the vascular system by raising the heart rate, hastening blood flow and opening the blood vessels. During times of stress or anxiety, this substance also affects the processing of glucose, offering access to additional stores of energy. In addition, noradrenaline works to heighten the human body's capacity to effectively manage strain by providing increased oxygen to the brain and greater blood flow to the muscular system.

It has been found that sufferers of depression and schizophrenia typically show imbalances in norepinephrine levels. The body's ability to manage the release and retention of the substance can be regulated with the help of medicinal interventions intended to adjust the amount of this key neurotransmitter that will be present the body. People who are afflicted by hypotension, or abnormally low blood pressure, can also benefit from the introduction of additional norepinephrine, as can those who suffer from septic and neurogenic shock. Medications formulated to raise noradrenaline levels have also shown promise in the treatment of attention-deficit/hyperactivity disorder. Given its central role in such a wide range of physiological processes and responses, the medicinal indications for norepinephrine only serve to underscore the breadth of its potential applications.