Effect of Prostaglandin E₁ on Blood Pressure and Heart Rate in the Dog Prostaglandin and related factors 48

Abstract

Abstract Prostaglandin E 1 (PGE 1 ) was infused into anesthetized dogs in aorta or i.v. in doses from 0.12 to 1.2 μg/kg/min. In all dogs a reproducible fall in blood pressure and increase in heart rate was obtained. Administration in aorta produced more pronounced changes than i.v. administration and infusion high in aorta was more effective than low in aorta. Infusion of PGE 1 into a common carotid artery elevated the blood pressure slightly in 6 of 8 dogs. PGE 1 produced a fall in blood pressure also in dogs treated with the sympathetic ganglionic blocking agent Agentit R and reserpine and with the beta‐adrenergic receptor blocking agent, propranolol (Inderal R ). In the Agentit R ‐treated animals infusion of PGE 1 into a common carotid artery produced a blood pressure fall, similar to that seen during i.v. infusion. There was no increase in heart rate during infusion of PGE 1 into the animals treated with Agentit R or reserpine. In dogs receiving continuous infusions of PGE 1 in doses lowering the blood pressure, infusions of noradrenaline or adrenaline still induced a marked rise in blood pressure. Infusion of the sympathetic ganglionic stimulating agent DMPP or electrical stimulation of the central ends of the cut vagus nerves also raised the blood pressure in dogs receiving PGE 1 The hypothesis was discussed that PGE 1 lowers the blood pressure by actions independent of catecholamines.