Effects of platelet-activating factor on rat mesenteric microcirculation.

The actions of platelet-activating factor (PAF) on rat mesenteric microcirculation were studied by laser Doppler microscopy in vivo. PAF 0.2 -0.6 micrograms/kg iv produced a dose-related decrease in the blood flow velocity and an increase in the diameters of the mesenteric arterioles and venules. These responses were completely reversed by pretreatment with PAF receptor antagonist SRI 63441. The results suggest that PAF may be a mediator of microcirculatory disturbances in the disease conditions associated with excessive PAF release.