Beta-1 adrenergic receptor

The beta-1 adrenergic receptor (β1 adrenoreceptor), also known as ADRB1, is an beta-adrenergic receptor, and also denotes the human gene encoding it.

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 noradrenaline, which, in turn, binds with higher affinity than adrenaline. Selective agonists to the beta-1 receptor are:
 * 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)

Mechanism
Gs renders adenylate cyclase activated, resulting in increase of cAMP.

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