Beta-1 adrenergic receptor

The beta-1 adrenergic receptor (β₁ adrenoreceptor), also known as ADRB1, is a beta-adrenergic receptor, and also denotes the human gene encoding it. It is a G-protein coupled receptor associated with the Gs heterotrimeric G-protein and is expressed predominantly in cardiac tissue.

Receptor

Actions

Actions of the β₁ receptor include:

• stimulate viscous, amylase-filled secretions from salivary glands
• Increase cardiac output
  • Increase heart rate in sinoatrial node (SA node) (chronotropic effect)
  • Increase atrial cardiac muscle contractility. (inotropic effect)
  • Increases contractility and automaticity of ventricular cardiac muscle.
  • Increases conduction and automaticity of atrioventricular node (AV node)
• Renin release from juxtaglomerular cells.
• Lipolysis in adipose tissue.
• Receptor also present in cerebral cortex.

Agonists

Isoprenaline has higher affinity for β₁ than adrenaline, which, in turn, binds with higher affinity than noradrenaline at physiologic concentrations. Selective agonists to the beta-1 receptor are:

• Denopamine
• Dobutamine (in cardiogenic shock)
• Xamoterol (cardiac stimulant)

Antagonists

(Beta blockers) β1-selective ones are:

• Acebutolol (in hypertension, angina pectoris and arrhythmias)
• Atenolol (in hypertension, coronary heart disease, arrhythmias and myocardial infarction)
• Betaxolol (in hypertension and glaucoma)
• Bisoprolol (in hypertension, coronary heart disease, arrhythmias, myocardial infarction and ischemic heart diseases)
• Esmolol (in arrhythmias)
• Metoprolol (in hypertension, coronary heart disease, myocardial infarction and heart failure)
• Nebivolol (in hypertension)
• Vortioxetine (antidepressant)

Mechanism

G_s renders adenylate cyclase activated, resulting in increase of cAMP.

Gene

Specific polymorphisms in the ADRB1 gene have been shown to affect the resting heart rate and can be involved in heart failure.

Interactions

Beta-1 adrenergic receptor has been shown to interact with DLG4 and GIPC1. Interaction between testosterone and β-1 ARs have been shown in anxiolytic behaviors in the basolateral amygdala.

See also

• Other adrenergic receptors
  • Alpha-1 adrenergic receptor
  • Alpha-2 adrenergic receptor
  • Beta-2 adrenergic receptor
  • Beta-3 adrenergic receptor