Table 1.
Adrenergic receptors-mediated responses of effector organs (9).
| Effector organs | Receptor type | Responses | Most relevant clinical manifestations |
|---|---|---|---|
| Eye | |||
| Radial muscle, iris | α1 | Contraction (mydriasis) ++ | Blurry vision |
| Ciliary muscle | β2 | Relaxation for far vision + | |
| Heart | |||
| SA node | β1, β2 | Increase in heart rate ++ | Palpitations, angina |
| Atria | β1, β2 | Increase in contractility and conduction velocity ++ | |
| AV node | β1, β2 | Increase in contractility and conduction velocity +++ | |
| His-Purkinje system | β1, β2 | Increase in contractility and conduction velocity +++ | |
| Ventricles | β1, β2 | Increase in contractility and conduction velocity, automaticity, and rate of idioventricular pacemakers +++ | |
| Arterioles | |||
| Coronary | α1, α2, β2 | Constriction +, dilations ++ | Angina |
| Skin and mucosa | α1, α2 | Constriction +++ | Pallor |
| Skeletal muscle | α1, β2 | Constriction ++, dilations ++ | Hypertension |
| Cerebral | α1 | Constriction (slight) | Stroke |
| Pulmonary | α1, β2 | Constriction +, dilations ++ | Edema |
| Abdominal viscera | α1, β2 | Constriction +++, dilations + | E.g., Bowel ischemia |
| Salivary glands | α1, α2 | Constriction +++ | |
| Renal | α1, α2, β1, β2 | Constriction +++, dilations + | Renal failure |
| Veins (systemic) | α1, α2, β2 | Constriction ++, dilations ++ | Orthostatic hypotension |
| Lung | |||
| Tracheal and bronchial muscle | β2 | Relaxation + | |
| Bronchial glands | α1, β2 | Decreased secretion; increased secretion | |
| Stomach | |||
| Motility and tone | α1, α2, β2 | Decrease (usually) + | Early satiety, discomfort |
| Sphincters | α1 | Contraction (usually) + | |
| Intestine | |||
| Motility and tone | α1, α2, β1, β2 | Decrease + | Constipation, ileus |
| Sphincters | α1 | Contraction (usually) + | |
| Secretion | α2 | Inhibition | Constipation |
| Gallbladder and ducts | β2 | Relaxation + | Gallstones |
| Kidney | |||
| Renin secretion | α1, β2 | Decrease +, increase ++ | |
| Urinary bladder | |||
| Detrusor | β2 | Relaxation (usually) + | Urinary retention |
| Trigone and sphincter | α1 | Contraction ++ | |
| Ureter | |||
| Motility and tone | α1 | Increase | |
| Uterus | α1, β2 | Pregnant: contraction; relaxation Nonpregnant: relaxation |
|
| Sex organs, male | α1 | Ejaculation ++ | |
| Skin | |||
| Pilomotor muscles | α1 | Contraction ++ | |
| Sweat glands | α1 | Localized secretion + | Sweating |
| Spleen capsule | α1, β2 | Contraction ++, relaxation + | |
| Skeletal muscle | β2 | Increased contractility; glycogenolysis; K+ uptake | Hyperglycemia, glycosuria |
| Pancreas | |||
| Acini | α | Decreased secretion + | |
| Islet (β cells) | α2 | Decreased secretion +++ | Hyperglycemia, glycosuria |
| β2 | Increased secretion + | Hypoglycemia | |
| Fat cells | α2, β1, β2 | Lipolysis +++ (thermogenesis) | Feeling warm |
| Salivary glands | α1 | K+ and water secretion + | |
| β | Amylase secretion + | ||
| Lacrimal glands | α | Secretion + | Lacrimation |
| Pineal gland | β | Melatonin synthesis | |
| Posterior pituitary | β1 | Antidiuretic hormone secretion | Decreased diuresis |