Definition

1. Noun:
   • A neurotransmitter and hormone: Norepinephrine is a chemical substance that functions both as a neurotransmitter in the nervous system and as a hormone in the bloodstream.
   • A catecholamine: It is a specific type of organic compound (a catecholamine) that acts as a precursor in the biological synthesis of epinephrine (adrenaline).
   • A stress-response chemical: It is secreted by the adrenal medulla and released at nerve synapses, playing a key role in the body's "fight-or-flight" response, increasing alertness, focus, and heart rate.

Usage Examples

• Noun:
  • The release of norepinephrine increases heart rate and blood pressure.
  • Some antidepressants work by affecting the reuptake of norepinephrine in the brain.
  • The adrenal glands secrete norepinephrine during stressful situations.

Advanced Usage

• In medical/physiological contexts: Often discussed in relation to the sympathetic nervous system, stress, mood disorders, and cardiovascular function.
  • The study focused on norepinephrine levels in patients with panic disorder.
• In pharmacology: Refers to a substance that can be administered as a medication (often called noradrenaline) to treat severe low blood pressure.
  • The patient was given an infusion of norepinephrine to support their blood pressure.

Variants and Related Words

• Noradrenaline: The British English and common international pharmacological term for norepinephrine. They are chemically identical.
• Catecholamine: The class of compounds to which norepinephrine belongs, also including dopamine and epinephrine.
• Neurotransmitter: The general category for chemicals like norepinephrine that transmit signals across a synapse.

Synonyms

• Noradrenaline (primary synonym, especially outside North America)

Related Compounds and Phrases

• Norepinephrine reuptake inhibitor (NRI): A type of drug that increases norepinephrine levels by blocking its reabsorption into nerve cells.
  • The medication is a selective norepinephrine reuptake inhibitor.
• Norepinephrine transporter (NET): The protein responsible for the reuptake of norepinephrine from the synapse.

Noun

1. a catecholamine precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses