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

• increases blood pressure

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