Bronchospasm is initiated by?: (A) C5a, (B) C3a, (C) Leukotrienes, (D) Acetylcholines
Answer is C. Ans. (c) Leukotrienes(Ref: Robbins 9th/pg 89)LTE4 cause intense vasoconstriction, bronchospasm (importantin asthma), and increased permeability of venules.C3a, C5a, and, to a lesser extent, C4a stimulate histamine release from mast cells and thereby increase vascular permeability and cause vasodilation. They are called anaphylatoxins