BIOASSAY OF VERATRUM VIRIDE. I. EFFECT OF VERGITRYL ON CAROTID SINUS PRESSOR REFLEX

¹ Squibb Institute for Medical Research, New Brunswick, New Jersey

Bioassay of Vergitryl, a semi-pure preparation derived from Veratrurn viride, has been achieved effectively and economically by producing graded decreases in the elicitable carotid sinus pressor reflex response in vagotomized anesthetized dogs. In this assay method the percentage decreases in this reflex response obtained with three cumulative doses are linear when plotted against log total dose. Dose-response curves for the standard and test sample are obtained in each assay. When a statistically significant combined slope and no significant curvature or departure from parallelism have been obtained, the relative potency and its limits of error are calculated.

The relative potency of Vergitryl obtained with the carotid sinus pressor reflex method in 2 to 6 vagotomized anesthetized dogs appears to be essentially the same as the hypotensive potency obtained in 13 to 16 intact anesthetized dogs. The changes in the pressor reflex response and the existent mean blood pressure are highly correlated. The former response serves as a more sensitive test variate since it yields a steeper dose-response curve than the hypotensive response.