Pharmacological Study of Phospholipase A₂-Induced Histamine Release from Rat Peritoneal Mast Cells

抄録

The effect of some drugs on phospholipase A₂ (PLA₂)-induced histamine release from rat peritoneal mast cells was investigated. 1. PLA₂ (Naja naja) caused the release of histamine from rat peritoneal mast cells in a dose related fashion. 2. The release of histamine by PLA₂ was decreased by the removal of each of calcium and glucose from the reaction medium (Tyrode's solution). 3. p-Bromophenacyl bromide and mepacrine, PLA₂ inhibitors, inhibited the release of histamine caused by PLA₂. 4. Cinnarizine and nifedipine, calcium channel blockers, and oxatomide, KC-404, tranilast and disodium cromoglycate, anti-allergic agents, also inhibited the PLA₂-induced histamine release. 5. When prednisolone (0.5 mg/kg) was administered i.p. 2, 3 and 4h prior to the harvest of the mast cells, the amount of histamine released by PLA₂ ex vivo was significantly decreased. Hydrocortisone, prednisolone and dexamethasone clearly inhibited the release of histamine from mast cells when they were administered 4h prior to harvest of the cells.