Adrenergic

Definition:

Adrenergic refers to the nervous system, receptors, or drugs that are associated with or affected by epinephrine (adrenaline) and norepinephrine (noradrenaline). The term is derived from the word “adrenaline,” which is one of the main hormones secreted by the adrenal glands.

Adrenergic Nervous System

Definition:

The adrenergic nervous system is a part of the autonomic nervous system that regulates various bodily functions by the release and binding of neurotransmitters called catecholamines. The primary catecholamines involved in adrenergic neurotransmission are epinephrine and norepinephrine. This system is responsible for the fight-or-flight response and helps regulate heart rate, blood pressure, and other vital functions.

Adrenergic Receptors

Definition:

Adrenergic receptors are specialized proteins located on the surface of target cells that bind with norepinephrine and epinephrine, thereby initiating a physiological response. There are two primary types of adrenergic receptors:

1. Alpha-adrenergic receptors: These receptors are further categorized into alpha-1 and alpha-2 receptors. Activation of alpha-adrenergic receptors leads to various effects such as vasoconstriction, increased blood pressure, and smooth muscle contraction.
2. Beta-adrenergic receptors: These receptors are further categorized into beta-1, beta-2, and beta-3 receptors. Activation of beta-adrenergic receptors results in effects such as increased heart rate and contractility, bronchodilation, and lipolysis.

Adrenergic Drugs

Definition:

Adrenergic drugs are medications that mimic or enhance the effects of epinephrine and norepinephrine on adrenergic receptors. These drugs are used to treat various medical conditions, including asthma, hypertension, and certain cardiac disorders. Depending on their specific mechanism of action, adrenergic drugs can selectively activate or block different subtypes of adrenergic receptors, leading to desired therapeutic effects.