Cardiovascular effects of prostaglandin F_2α and prostaglandin E₂ in Atlantic cod (Gadus morhua)

Abstract.

Little is known of the cardiovascular functions of prostaglandins in non-mammalian vertebrates. There are indications that prostaglandins may have a function in haemostasis by constricting blood vessels in filament arteries in the fish gill after injury. Our aim was to examine the cardiovascular effect of the prostaglandins F_{2 α} (PGF_{2 α}) and E₂ (PGE₂) with emphasis on branchial circulation. Intra-arterial injections of PGF_{2 α} (10, 40, 160, 400 nmol kg^–1) in cod caused a dose-dependent increase in ventral aortic blood pressure, a reduction in cardiac output, and an increase in gill vascular resistance. A contraction of filament arteries was observed with in vivo microscopy only seconds after injection. PGF_{2 α} may therefore possibly be involved in a haemostatic vasoconstriction. In contrast, the most significant effects of PGE₂ appeared to be on the heart. PGE₂ also reduced dorsal aortic blood pressure.