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ON THE ACTION OF VERATRUM VIRIDE: WITH SOME REMARKS ON THE INTERRELATIONSHIP OF THE MEDULLARY CENTRES

1915; American Society for Pharmacology and Experimental Therapeutics; Volume: 7; Issue: 1 Linguagem: Inglês

1521-0103

William A. Cramer,

Pediatric Hepatobiliary Diseases and Treatments

Veratrum viride in small doses has a selective action on the afferent (pulmonary) nerve-endings of the vagus. In cats it thus produces reflexly slowing or stoppage of respiration and a fall of blood-pressure due to vaso-dilatation. As a rule there is in addition a marked slowing of the heart-beat produced reflexly through vagus-inhibition, but in cats this effect is sometimes absent. These effects of small doses are dependent on the integrity of the vagus nerves. The drug after having stimulated the afferent nerve-endings of the vagus, paralyses them so that a second or third dose is without effect. With larger doses the drug in addition to the effects just mentioned, paralyses the cardio-inhibitory nerve-endings of the vagus and has also a direct action on the medullary centres leading to vaso-constriction and to paralysis of respiration. These additional effects are not dependent on the integrity of the vagus nerves. Since large doses of the drug have so many diverse and partly antagonistic actions, the general result of a large dose of veratrum viride is very complex and irregular. The manner in which veratrum viride acts reflexly on the medullary centres leads to the conclusion that impulses arriving at the respiratory centre can be communicated to the vasomotor centre and to the cardio-inhibitory centre and that a central connection exists between these medullary centres. The question whether veratrum viride owes its action to veratrine or to protoveratrine or to another alkaloid is discussed and left undecided. It is pointed out, however, that in the light of the present observations, the pharmacological action of veratrine and protoveratrine requires reinvestigation. Veratrum viride is therapeutically valuable, as in suitable doses it affords a means of producing a lasting vaso-dilatation through acting reflexly on the vaso-motor centre.