Adrenergic receptors
Adrenergic receptors are of two types: alpha and beta.
Epinephrine vs norepinephrine
Epinephrine - excites both equally
- increases cardiac output
- increases blood pressure slightly
Norepinephrine - excite mainly alpha receptors
Stimulation of receptors
See also 'Effects of ANS stimulation'
Stimulation of alpha-1 receptors results in:
- vasoconstriction
- increased peripheral resistance
- increased blood pressure
- mydriasis (dilation of iris/pupil)
- increased tone in internal sphincter of urethra
- increased tone in intestinal sphincter
Stimulation of alpha-2 receptors results in:
- Inhibition of norepinephrine release
- Inhibition of insulin release
Stimulation of beta-1 receptors results in:
- Tachycardia
- Increased lipolysis
- Increased myocardial contractility
Stimulation of beta-2 receptors results in:
- Skeletal muscle vasodilation
- Slightly decreased peripheral resistance
- Bronchodilation
- Increased muscle and liver glycogenolysis
- Increased release of glucagon
- Uterine relaxation
