adrenoceptor -β

Isoprotrenol > epine >nor epi

β-1:

affinity epine = nor epine

mech: G-pr stimulate cAMP

location:myocardium , kidney ,

fat cell

The effect of β-1

- tachycardia

-increase force and rate of

contraction

(inotropic and chronotropic)

-increase lipolysis

-increase renin secretion by

kidney

β-2:

affinity epine > nor epine

mech: G-pr stimulate cAMP

location :

-sm of BV in sk m, bronchial tree,

urinary bladder & uterus

-liver

-α-cell of pancreas

-pump that shift K+ into cell

β-3= lipolysis

The effect of β-2:

-Vasodilatation in sk m (artery & vein)

-bronchodilation

-relaxation of detrusor sm& GIT SM

-constriction of GIT sphincters

-relaxation of uterine sm

-increase glycogenolysis in liver& gluconeogenesis

-increase release of glucagon

-induce hypokalemia

-increase lipolysis

-decrease release of autacoids

:Adrenergic receptors

Beta 2 receptors are present

on the ciliary epithelium

Beta 2 blocking agents reduce the

production of aqueous humor and

decrease IOP.