MECHANISM OF VERATRUM-INDUCED EMESIS IN THE CAT

¹ Department of Pharmacology, University of Utah, College of Medicine, Salt Lake City

Experiments were performed in cats to determine the site of emetic action of Veriloid, a partially purified derivative of Veratrum viride. Chronic ablation of the chemoreceptor trigger zone in the medulla did not impair Veriloid-induced emesis. Decerebrate cats were subjected to a series of neurological operative procedures designed to eliminate structures non-essential to the vomiting reflex initiated by Veriloid. Chronic preparations were utilized to substantiate the negative results with intravenous Veriloid in acute experiments. Gut denervation did not significantly alter the emetic responsiveness to oral Veriloid.

This study demonstrates that the receptors for Veriloid emesis are situated either within the nodose ganglion or in close proximity to it. Neither vagal section below the nodose ganglion nor decapsulation of the ganglion interfered with the elicitation of emesis, but interruption of the vagus above the nodose ganglion invariably prevented emesis in response to Veriloid.

It is suggested that the adequacy of current theories on the mechanism of veratrum-induced vasodepression be reexamined in view of the possible role of the nodose ganglion as a receptor site for the hypotensive action.

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