Woohoo! My favorite receptors! Adrenergic receptors activate the sympathetic branch of the autonomic nervous system. So, adrenergic agonists are known as sympathomimetics, that is, they mimic a sympathetic, or “fight or flight”, response. Adrenergic antagonists are called sympatholytics.
1. There are FIVE very important subtypes of adrenergic receptor (these will be addressed in detail later). They are: alpha-1, alpha-2, beta-1, beta-2, and Dopamine.
2. The main neurotransmitter that activates adrenergic receptors is Norepinephrine (NE).
3. Adrenergic receptors are located all over the body, including the heart, blood vessels, digestive tract, and even in the uterus!
4. Agonism or antagonism of an adrenergic receptor can be accomplished by binding to the receptor directly, blocking the receptor, or messing with the release, clearance, or binding of norepinephrine.