During the rolling phase of neutrophil margination, histamine released at an injured site causes rapid surface expression of an adhesion molecule within minutes. Where is this molecule stored before release?

• A Specific granules of neutrophils
• B Weibel-Palade bodies of endothelial cells ✓
• C Golgi cisternae of smooth muscle cells
• D Platelet alpha granules

Explanation

P-selectin (CD62P) is preformed in Weibel-Palade bodies of endothelial cells and platelet alpha granules; histamine and thrombin trigger its rapid redistribution to the luminal surface, initiating neutrophil rolling via its ligand sialyl-Lewis X-modified glycoproteins. Neutrophil granules contain proteases such as elastase, and E-selectin is synthesized de novo over hours rather than being prestored in Weibel-Palade bodies.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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