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Prostacyclin (PGI2) Elicits Reflex Bradycardia in Dogs: Evidence for Vagal Mediation

1979; SAGE Publishing; Volume: 162; Issue: 1 Linguagem: Inglês

10.3181/00379727-162-40625

1535-3702

Thomas H. Hintze, Eugene Martin, E. J. Messina, Gabor Kaley,

Cardiovascular Syncope and Autonomic Disorders

SummaryAdministration of the vasode-pressor prostaglandins, PGE1 and PGE2, and of nitroprusside, an agent whose direct vascular activity is similar to prostaglandins, resulted in a reduction in systemic arterial blood pressure accompanied by the expected reflex increase in heart rate. Injection of pros-tacyclin (PGI2) and the prostaglandin precursor, arachidonic acid, into the femoral vein, pulmonary artery, left atrium, and left ventricle of the dog elicited a fall in blood pressure and a concomitant reduction in heart rate in both open- and closed-chest anesthetized dogs. Bilateral vagal section eliminated the bradycardia thus establishing that the PGI2-induced change in heart rate is reflex in origin.Prostacyclin and prostaglandins were provided by Dr. U. Axen and Dr. J. Pike (Upjohn Co.). Dial-urethane was a gift from Ciba-Geigy. We are grateful to Messrs. Arsenio Baez and Maret Panzenbeck for excellent technical assistance.