Adrenergic Receptors and Their Predominant Physiological Effects

Adrenergic receptors, also known as adrenoceptors, are cell surface glycoproteins that recognize and selectively bind the catecholamines, norepinephrine and epinephrine to stimulate the nerves in your body’s sympathetic nervous system (SNS). Here is a list of cholinergic receptors and their major pharmacological effects:


  • α1 (Iris radial muscle) – Pupillary dilation
  • β2 (Ciliary muscle) – Relaxation for far vision 


  • β1, β2 (Sinoatrial, atrioventricular nodes) – Increased spontaneous depolarization
  • β1, β2 (His-Purkinje system) – Increased conduction velocity
  • β1, β2 (Atria, ventricles) – Increased contractility

Blood vessels

  • α1, α2, β2 (Arteries, arterioles) – Constriction via α1, α2; dilation via β2
  • α1, α2, β2 (Veins, venules) – Constriction via α1, α2; dilation via β2


  • β2 (Tracheal, bronchial muscle) – Relaxation of smooth muscle
  • α1, β2 (Bronchial glands) – Decreased secretions

GI tract

  • α1 (Salivary glands) – Decreased secretions
  • α1, α2, β2 (Stomach) – Decreased motility; decreased secretions
  • α1, β2 (Intestines) – Decreased motility

Urinary bladder

  • β2 (Detrusor) – Relaxation, increased capacity
  • α1 (Trigone, sphincter) – Contraction

Sex organs 

  • α1 – Ejaculation

Skeletal muscle

  • β2 – Increased contractility; glycogenolysis


  • α1, β2 – Increased glycogenolysis


  • β2 – Increased insulin release

Fat cells 

  • β1, β2, β3 Lipolysis


  • α1, β1 – Increased renin release

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