BRADYKININS.pptx

BRADYKININS

1. BRADYKININS Dr. Sarita Sharma Associate Professor MMCP, MMDU

2. BRADYKININS Inflammatory mediator Bradykinin is a 9-amino acid  peptide chain . The  amino acid  sequence of bradykinin is:  Arg - Pro - Pro - Gly - Phe - Ser - Pro - Phe - Arg (RPPGFSPFR). Its empirical formula is therefore C 50 H 73 N 15 O 11 . Bradykinin formed by proteolytic cleavage of circulating proteins termed kininogens ( biologocal peptide).

3. Biosynthesis: The  kinin-kallikrein system  makes bradykinin by    kininogen  precursor proteolytic cleavage high-molecular-weight kininogen (HMWK) enzyme  kallikrein active ( serine proteases , ) bradykinin Pre- kallikrein inactive Hagemen’s factor (factor XII)

4. KININS RECEPTORS, ACTIONS & THERAPY Activate β 1 , β 2 , β 3 receptors linked to PLC/A 2 Powerful Vasodilation→ decreased blood pressure via  2 receptor stimulation Increase in capillary permeability inducing edema. Produces inflammation & pain. (  2 ) Cardiac stimulation: Compensatory indirect & direct tachycardia & increase in cardiac output It produces coronary vasodilation

5. PHARMACOLOGICAL ACTIONS Vasodilatation Increased vascular permeability Stimulation of epithelial ion transport and fluid secretion in airways and gastrointestinal tract

6. KININS ACTIONS & THERAPY Kinins produce broncho-constriction & itching in respiratory system Therapeutic Use: No current use of kinin analogues Increased Bradykinin is possibly involved in the therapeutic efficiency & cough produced by ACEIs ACE inhibitors BP & bradykinins