Location and Functions of Receptors
| Organ / System | Cholinergic Response (via receptors) | Adrenergic Response (via receptors) |
|---|---|---|
| HEART | Decreased Rate (chronotropy), Force of Contraction (inotropy) and Conduction (dromotropy) – M2 | Increased Rate, Force of Contraction, and Conduction – β1 |
| BLOOD VESSELS | Dilation mediated by nitric oxide (M3) | Constriction (α1) Dilation (β2) |
| BRONCHUS | Bronchoconstriction (M3) | Bronchodilation (β2) |
| EYE | ||
| Iris, radial muscle | Contraction (mydriasis) – α1 | |
| Iris, sphincter muscle | Contraction (miosis) – M1/M3 | |
| Iris, ciliary muscle | Contraction (near vision) – M1/M3 ● relaxation of zonula fibers ● opening pores of trabecular meshwork | Relaxation (far vision) – β2 |
| Ciliary epithelium | α2 - decrease aqueous production β2 - increase aqueous production |
|
| GASTROINTESTINAL TRACT | ||
| Motility | Increased (M3) | Decreased (α1) |
| Sphincters | Relaxation (M3) | Constriction (α1) |
| Secretions | Increased (M1/M3) | Decreased (α1) |
| URINARY BLADDER | ||
| Detrusor | Contraction (M3) | Relaxation (β3) |
| Trigone and sphincter | Relaxation (M3) | Contraction (α1) |
| SWEAT & SALIVARY GLANDS | Increased secretion (M1/M3) | Increased secretion (α1) |
| UTERUS | Contraction (α1) Relaxation (β2) |
|
| SKELETAL MUSCLE | Contraction (Nm) | |
| KIDNEYS | Renin secretion (β1) | |
| GENITALS | Erection – M3 receptors located on penile blood vessels | Ejaculation – α1 receptors located on vas deferens and prostate capsule |
| METABOLIC | Decreased insulin secretion (α2) Increased insulin secretion and gluconeogenesis – β2 Lipolysis (β3) |
|
| PRESYNAPTIC NERVE TERMINALS | Decrease ACh release (M1) | Decrease NE release (α2) |
| AUTONOMIC GANGLIA | Cholinergic neurotransmission – Nn | Adrenergic neurotransmission – Nn |
