Characterization of Protease-Activated Receptors in Rat Peritoneal Mast Cells

Abstract

Activation of protease−activated receptor(PAR)−1 or PAR−2 elicits inflammation most probably via mast cell degranulation in vivo.The present study aimed at characterizing PARs in rat peritoneal mast cells(PMC).Messenger RNA for PAR−1, but not for PAR−2, was detected in PMC.Thrombin, the PAR−1 agonist SFLLR−NH₂ or the PAR−2 agonist SLIGRL−NH₂ failed to induce histamine release from PMC.Surprisingly, the PAR−2−inactive control peptide LSIGRL−NH₂ triggered histamine release from PMC.Thus, PAR−1, but not PAR−2, are expressed in PMC, whereas neither PAR−1 nor PAR−2 are considered to be involved in degranulation of PMC.LSIGRL−NH₂ does not appear to be appropriate as a control peptide for PAR−2 in inflammation studies.