Celtarys – What is the Function of the Adrenergic Receptor?

Adrenergic receptors are found on the surface of the cells of tissues and organs in our bodies and is crucial in regulating the sympathetic nervous system (SNS). The important role of the adrenergic receptors includes activating our ‘fight-or-flight’ responses and helping to regulate cardiovascular functions like lowering blood pressure. This article will cover the main functions of adrenergic receptors and their classifications.

What is an Adrenergic Receptor?

Adrenergic receptors are classed as G protein-coupled receptors (GPCRs) and are targeted by catecholamines like norepinephrine and epinephrine. Once activated, these receptors generate certain sympathetic and parasympathetic effects in our body as part of the ‘fight or flight’ and ‘rest and digest’ responses, respectively. 

Initially, it was believed there were two types of adrenergic receptors: alpha and beta-adrenoreceptors. However, due to extensive research and developments, there are now three classified groups: alpha-1 (α1), alpha-2 (α2), and beta (β). Each type has three subtypes of receptors within, increasing the full list of receptors to the following (1):

α1 ARs

α2 ARs

β ARs










Once activated, the adrenergic receptors mediate physiological signals from the sympathetic nerve endings. The responses of the receptors vary between the alpha and beta receptors, although the intended outcome of protecting the body is the same. The alpha receptors function by stimulating effector cells whereas the beta receptors relax them. Their responses include artery, cardiac and muscle contraction, which leads us to introduce the importance of these receptors in managing cardiovascular disorders, among other roles (2).

What is the Function of the Adrenergic Receptors?

Now that we have provided a brief overview of what adrenergic receptors are, let us discuss their functions. Adrenergic receptors have a complex role in the human body. They respond to disease, fear and other issues in a way that helps to protect our bodies and aims to keep us safe. In the following section, we will provide examples of some of their key roles.

Alpha-Adrenergic Receptors

When activated, alpha-adrenergic receptors will control physiological processes such as intestinal relaxation, pupil dilation, smooth muscle contraction and vasoconstriction. These activities are initiated when norepinephrine and epinephrine are released and bind themselves onto adrenergic receptors on certain organs (3). Additionally, alpha-ARs play a part in lowering or regulating blood pressure.

Beta-Adrenergic Receptors

Beta-adrenergic receptors (β1, β2 and β3) are involved in smooth muscle relaxation, especially in the ureter, bladder, prostate and urethra, regulating cardiac functions and specifically playing a vital part in heart failure and cardiac disease (4). Beta receptors are known for their cardiac impact such as increasing contractility, heart rate and relaxation rate, but they also have a role in bronchodilation, hepatic glycogenolysis, releasing renin in the kidneys and releasing glucagon in the pancreas (5).

Celtarys and Adrenergic Receptors

Celtarys utilizes proprietary technology to help clients develop more efficient high throughput screening (HTS) processes and supports the synthesis of fluorescent ligands. One of our core products includes the CELT-130 and CELT-133. Adrenergic receptor antagonists are used for treating a wide range of problems, especially cardiac diseases because they help to reduce blood pressure and relieve hypertension. Additional uses include treating pain and panic disorders.

If you are looking for fluorescent ligands for Adrenergic receptors with high affinity, validated on many different applications (i.e: Flow cytometry, Fluorescent polarization) or would like more information on adrenergic receptors, don’t hesitate to contact us today.


  1. Hayward, L. F., Mueller, P. J., & Hasser, E. M. (2004). Adrenergic receptors.
  2. Graham, R. M. (1990). Adrenergic receptors: structure and function. Cleveland Clinic journal of medicine, 57(5), 481-491.
  3. Adrenergic Receptors: Team Alpha. (2022). EZMed.
  4. Archer, M., Dogra, N., Dovey, Z., Ganta, T., Jang, H. S., Khusid, J. A., ... & Kyprianou, N. (2021). Role of α-and β-adrenergic signaling in phenotypic targeting: significance in benign and malignant urologic disease. Cell Communication and Signaling, 19(1), 1-21.
  5. Klabunde, R. E. (2022).Beta-Adrenoceptor Agonists (β-agonists). Cardiovascular Pharmacology Concepts.