Platelet activating factor potentiates rat paw oedema induced by different phlogogen agents.

Carrageenin oedema is enhanced by the simultaneous injection in the rat paw of platelet activating factor (PAF). The enhancement of carrageenin oedema is observed throughout the time course of the experiments. This enhancement is also present when the oedema-producing agent is dextran, cellulose sulphate, histamine, 5-hydroxytryptamine, bradykinin or prostaglandin E2. Both verapamil and BN 52021 abolished the enhancement induced by PAF without modifying significantly carrageenin oedema. In essential fatty acid deficient (EFAD) rats depleted of kininogen and amines, carrageenin oedema is not modified by PAF. These findings suggest that PAF interacts with other inflammatory mediators regulating the formation of oedema induced by irritants injected locally.