Page 186 - pharma 1 theoretical updated MNU_Neat

Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)
Platelet activating factor (PAF)

• PAF is a phospholipid-derived mediator released by the action of phospholipase A2

from activated inflammatory cells.
• It causes VD, increase vascular permeability, chemotaxis, and activation of leukocyte,
activation and aggregation of platelet, and smooth muscle contraction.

• It is potent Pathophysiological mediator of asthma and shock
• significant role as chemoattractant for eosinophils (eosinophile higher levels in

Asthma)
• Lexipafant is PAF antagonist, used in cases of Pancreatitis.

Vasoactive peptides

● Several peptides exert important direct effects on vascular and other smooth muscles.

● These peptides include:

➢ Vasoconstrictors (angiotensin II, vasopressin, endothelin)

➢ Vasodilators (bradykinin and related kinins, natriuretic peptides, substance P).

The Renin-Angiotensin System (RAS)

● The renin-angiotensin system is an important control system involved in the regulation
of blood pressure, fluid and electrolyte balance, and other functions.
● Over-activity of this system has been implicated in hypertension, heart failure, and

other diseases.
● Drugs that block the formation or actions of angiotensin-II (ANG-II) are used extensively
in the treatment of these diseases.

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