Norepinephrine (NE)

What is norepinephrine and what is it used for in the body?

Norepinephrine (NE) is a neurotransmitter that is produced and released by the sympathetic nervous system. It is responsible for activating the "fight or flight" response in the body, which increases heart rate, blood pressure, and other physiological changes that help prepare the body for emergency situations. NE is also involved in the regulation of mood and attention, and it has been shown to have antidepressant and stimulant effects.

How is norepinephrine measured in the body?

Norepinephrine can be measured in the body through various laboratory tests, including blood tests and urine tests. In blood tests, NE levels are typically measured in the plasma, which is the liquid portion of the blood. In urine tests, NE is usually measured as a breakdown product called vanillylmandelic acid (VMA).

What is the normal range for norepinephrine levels in the body?

The normal range for NE levels in the body varies depending on the method used to measure it and the specific laboratory that performs the test. In general, normal NE levels in the plasma are typically between 100 and 600 picograms per milliliter (pg/mL). In urine, normal NE levels are typically between 5 and 25 milligrams per gram of creatinine (mg/g Cr).

What can cause abnormal norepinephrine levels in the body?

Abnormal NE levels in the body can be caused by a variety of factors, including medical conditions such as hypertension (high blood pressure), hypoglycemia (low blood sugar), and pheochromocytoma (a rare tumor of the adrenal gland). In addition, certain medications, such as tricyclic antidepressants and monoamine oxidase inhibitors, can affect NE levels in the body.

How is norepinephrine related to the diagnosis of pheochromocytoma?

Pheochromocytoma is a rare tumor of the adrenal gland that can cause the overproduction of NE and other catecholamines, leading to high blood pressure and other symptoms. NE levels can be measured through blood or urine tests as part of the diagnostic process for pheochromocytoma. Elevated NE levels in the plasma or urine may be suggestive of the presence of this tumor.

How is norepinephrine related to the treatment of depression?

Norepinephrine has been shown to have antidepressant effects and is often used in the treatment of depression. Several classes of antidepressant medications, including tricyclic antidepressants and selective norepinephrine reuptake inhibitors (SNRIs), work by increasing the availability of NE in the brain.

Are there any potential side effects associated with norepinephrine medications?

Like all medications, norepinephrine-based medications can have potential side effects. These may include dry mouth, constipation, dizziness, drowsiness, and difficulty urinating. In rare cases, more serious side effects such as irregular heartbeat, fainting, or allergic reactions may occur. It is important to discuss potential side effects with a healthcare provider before starting any medication.