Studies on the hypotensive effects of platelet activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) in rats, guinea pigs, rabbits, and dogs.

Platelet activating factor (PAF) showed profound and long-lasting hypotensive effects in normotensive and spontaneously hypertensive rats, guinea pigs, rabbits and dogs. Sensitivity to PAF was different among the animal species. The magnitude and duration of the hypotensive effect was dose-dependent. Pharmacological studies suggested that the hypotensive action was unlikely to be caused by the actions on the central or autonomic nervous systems but seemed to be mainly due to some direct action(s) on the peripheral blood vessels.