β- adrenoceptor
TRANSCRIPT
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.