Platelet activating factor and histamine effects in synovial blood flow evaluated by laser-Doppler flowmetry.

Objective. To investigate platelet activating factor (PAF) and histamine effects in synovial circulation of rabbits. Methods. A laser-Doppler flowmeter was adapted to study the synovial blood flow. Either PAF or histamine were infused in the first femoral artery branch. The effects of PAF and histamine antagonists as well as of inhibitors of cycloxygenase products were evaluated. Results. PAF induced a vasoconstriction in synovial circulation, which was inhibited by the PAF antagonist, WEB 2170, a cycloxygenase inhibitor, indomethacin or a thromboxane synthesis inhibitor, dazmegrel