Cardiovascular effects of prostaglandins mediated by the central nervous system of the dog

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Abstract
1 Prostaglandins A1, E1, F1α and F2α were infused into the vertebral artery of the chloralose-anaesthetized greyhound and the resulting cardiovascular responses were compared with those obtained on intravenous and intracarotid infusions in the same dose range. 2 Infusions of PGF2α intravertebrally (4–64 (ng/kg)/min) caused an increase of blood pressure, tachycardia and a fall of central venous pressure. Cardiac output was increased and peripheral resistance was essentially unchanged. There was never any response to intravenous or intracarotid PGF2α infusions in this dose range. 3 PGF1α was found to have similar effects to PGF2α but it was much less potent. 4 PGE1 infusions (4–360 (ng/kg)/min) into the vertebral artery caused a tachycardia which was greater than that obtained with intracarotid or intravenous infusions, but there was no significant effect on blood pressure. 5 Infusions of PGA1 caused a small fall of blood pressure accompanied by an increase of heart rate and the dose response relationships were similar for all three routes of administration. 6 It is concluded that some prostaglandins can activate cardioregulatory centres within the territory of distribution of the vertebral artery. Prostaglandin F2α is the most potent of these.