Alterations in Cardiovascular Responses of the Dog Following Rauwiloid. An Alkaloidal Extract of Rauwolfia serpentina

Abstract

Rauwiloid, an alkaloidal mixture representing the total activity of the root of Rauwolfia serpentina, Benth., was admn. orally for 5 days to 15 dogs at a dose of 0.5 mg./kg./day. The following observations (compared to 15 control animals) were obtained on the 6th day: (l)Mean arterial pressure and heart rate decreased significantly; (?* sedation in 11; (3) increase of the pressor response to epinephrine; (4) enhancement of the hypotensive and cardio.accelerator effecte of isopropylnorepinephrine (Isuprel); (5) reversal of the blood pressure rise generally evoked by hypoxia; (6) decrease in the carotid sinus pressor reflex; (7) blockade of the primary blood pressure rise elicited by faradization of the afferent vagus the secondary rise being essentially unaltered; (8) no change in the hypotensive responses to acetyl-choline, histamine, and efferent vagal faradization. It remains to be shown whether this depression of reflex pressor responses (carotid body, carotid sinus, vagal) is causal to the hypotension.