Comparative effects of PGD 2 and PGE 2 on vasoconstrictor responses in the feline intestinal vascular bed

Abstract

The effects of prostaglandins (PG) D 2 and E2 on vascular resistance and vasoconstrictor responses were compared in the feline mesenteric vascular bed under conditions of controlled flow so that changes in perfusion pressure directly reflect changes in vascular resistance. Infusions of PGD 2 into the superior mesenteric artery significantly dilated the mesenteric vascular bed and inhibited vasoconstrictor responses to sympathetic nerve stimulation and intra-arterial injections of norepinephrine and angiotensin II. The inhibitory effects of PGD were reversible and dose-dependent. PGD 2 inhibited responses to sympathetic nerve stimulation to a greater extent than responses to the pressor hormones. Infusion of PGE 2 at similar doses dilated the mesenteric vascular bed but had little or no effect on vasoconstrictor responses to sympathetic nerve stimulation or pressor hormones. These data suggest that PGD 2 possesses the ability to modulate responses to nerve stimulation and pressor hormones by both pre- and post-junctional actions in the feline mesenteric vascular bed.