2-Minute Neuroscience: Norepinephrine

Norepinephrine, also known as noradrenaline, is a neurotransmitter and hormone that plays critical roles in the function of the nervous system. In this video, I discuss norepinephrine synthesis, where norepinephrine-producing neurons are concentrated, norepinephrine receptors, and the functions of norepinephrine.

TRANSCRIPT:

Norepinephrine, also known as noradrenaline, is a monoamine neurotransmitter, a term that refers its chemical structure and the fact that it’s derived from an amino acid. It is also a catecholamine, a term that again refers to its chemical structure and the fact that it contains a catechol nucleus. Norepinephrine also functions as a hormone. It is synthesized from dopamine in a reaction catalyzed by the enzyme dopamine beta-hydroxylase.

Norepinephrine-producing neurons in the central nervous system are primarily concentrated in the pons and medulla. The most prominent of these groups of neurons is a nucleus called the locus coeruleus, which is the main site of norepinephrine production for the central nervous system. Norepinephrine is also the primary neurotransmitter used by the sympathetic nervous system, and is found in clusters of sympathetic neurons located near the spinal cord known as sympathetic ganglia. It is also released from the adrenal glands as a hormone.

Norepinephrine acts on g protein-coupled receptors referred to as adrenergic receptors or adrenoceptors. There are thought to be at least three main types of adrenergic receptors, alpha-1, alpha-2 and beta-adrenergic receptors, each of which has multiple subtypes. Norepinephrine is removed from the synaptic cleft by a transport protein called the norepinephrine transporter.

Like any neurotransmitter, the actions of norepinephrine depend on the type of receptor it activates, and where that receptor is located. Thus, although norepinephrine in the central nervous system is frequently associated with arousal, alertness, and attention, the full extent of its actions are more complex. Its release in the sympathetic nervous system is typically associated with responses linked to increased activity, like elevated heart rate and blood pressure.

References:

Bylund DB. Adrenergic Receptors: Historical Perspectives from the 20th Century. In: Perez DM, ed. The Adrenergic Receptors. Totawa, New Jersey: Humana Press, Inc.

Szabadi E. Functional neuroanatomy of the central noradrenergic system. J Psychopharmacol. 2013 Aug;27(8):659-93. doi: 10.1177/0269881113490326.

Tank AW, Lee Wong D. Peripheral and central effects of circulating catecholamines. Compr Physiol. 2015 Jan;5(1):1-15. doi: 10.1002/cphy.c140007.

Wehrwein EA, Orer HS, Barman SM. Overview of the Anatomy, Physiology, and Pharmacology of the Autonomic Nervous System. Compr Physiol. 2016 Jun 13;6(3):1239-78. doi: 10.1002/cphy.c150037.

Видео 2-Minute Neuroscience: Norepinephrine канала Neuroscientifically Challenged