Page 28 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)

Adrenergic Receptors

Epinephrine & Norepinephrine ➔ bind to receptor ➔ activate coupled G protein ➔ change

in the cell ➔ action.

Site Action

α. Smooth muscles, blood vessels, liver. • Contraction of Smooth Muscle

• V.C of blood vessels

Sphincter of GIT, bladder Contraction ➔ slow passage of food

α1 & urine
Radial muscle of the iris of the eye Contraction  dilation of eye pupil

NE ➔ bind to α1 ➔ activation G-proteins ➔ activation of phospholipase C 
IP3  ↑ cytoplasmic concentration of Ca+2

Presynaptic. ↓ release of NE ➔ -ve feedback

control ➔↓ B. P
α2
NE ➔ bind to α1 ➔ activation G-proteins ➔ inhibition of adenylyl cyclase  ↓

cAMP

Heart • SA node ➔↑ heart rate

• Av node ➔↑ conduction velocity
β1
• Arterial & Ventricular ➔ ↑ force of

contraction

Smooth muscle of blood vessels in Vasodilation

β. skeletal muscle
Bronchioles Bronchodilation
β2
Wall of GI, bladder, uterus relaxation

NE ➔ bind to β1 & β2 ➔ activation G-proteins ➔ activation of adenylyl

cyclase  ↑ cAMP

Β3 Adipose tissue Lipolysis

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