STUDIES ON VERATRUM ALKALOIDS

III. QUALITATIVE AND QUANTITATIVE DIFFERENCES IN THE ACTION OF CEVINE AND VERATRIDINE

¹ From the Department of Pharmacology, Harvard Medical School, Boston, Mass.

The qualitative and quantitative differences between cevine and its veratric acid ester, veratridine, on the isolated frog heart, on the blood pressure and respiration of the cat, and in unanesthetized mammals have been studied.

Cevine and veratridine cause reversible systolic standstill of the isolated frog heart and, in lower concentrations, improve the activity of the frog heart made hypodynamic by perfusion with calcium-poor salt solution. In confirmation of what has been observed in the isolated and denervated mammalian heart, there are only quantitative differences in the heart action of the two substances.

The primary effect of cevine in mammals is a convulsant one with no appreciable action on the circulation, while that of veratrine is a profound respiratory depression and a marked circulatory action caused chiefly by vagal stimulation.

Veratridine increases the liberation of epinephrine from the suprarenal glands. This constitutes at least one factor in the increase in blood pressure seen in the spinal animal after administration of cevine esters.

The qualitative effects of veratridine are indistinguishable from those of veratrine.