Mechanisms of vascular actions of PAF

Abstract

The vascular actions of platelet-activating factor (PAF) in the coronary circulation in vitro (rat, guinea-pig) and the intracranial circulation in vivo in the anaesthetized pig have been examined. PAF elicited platelet-independent coronary vasoconstrictor responses which were associated with the release of vasoactive amounts of cyclo-oxygenase and lipoxygenase products. Vasoconstrictor responses in rat hearts showed a greater dependence on the release of leukotriene (LT) C4 than those in guinea-pig hearts. In addition, the latter species was considerably more sensitive to the coronary vasoconstrictor actions of PAF. Intra-arterial administration of PAF in the pig evoked biphasic changes in ..