Definition of prostaglandin-sensitive arterial constrictor systems

The effects of a number of prostaglandins on the systemic arterial circulations of the sheep, pig, dog, cat, rabbit and rat have been investigated. It is suggested that all of the species may possess, in addition to a PGE2-sensitive dilator system, a PGD2-sensitive constrictor system, and that 13,14-dihydro-15-oxo PGD2 is a potent and selective agonist on this system. The dog and the pig also have an endoperoxide-sensitive constrictor system activated by the 11,9-(epoxymethano) analogue of PGH2 and, of particular note, ICI 79939 and its 11-oxo analogue. These latter substances also contract the rabbit aorta strip and the guinea pig tracheal chain and aggregate human platelets. A number of PGF2alpha analogues show certain other distinctive cardiovascular actions.