THE ACTION OF IODOACETATE AND FLUORIDE ON THE ISOLATED RABBIT'S AURICLE

¹ Department of Pharmacology, University of Edinburgh

1. lodoacetate inhibits aerobic as well as anaerobic activity of the isolated rabbit's auricle. Under aerobic conditions, a rabbit's auricle inhibited by iodoacetate can be revived by lactate, pyruvate, phosphoglycerate, and propionate. Glucose, glycerophosphate, caproate, butyrate, valerate, malate, succinate, fumarate, and amino-acids, including glycine, alanine, and glutamic acid, have no revival effect.

2. Fluoride has no action upon the aerobic activity of the frog's heart and the rabbit's auricle but inhibits their anaerobic activity.

3. lodoacetate is believed to inhibit the formation of glycerophosphate and phosphoglyceric acid from triosephosphate and fluoride to prevent the conversion of phosphoglyceric acid to phosphopyruvic acid. If these conclusions are accepted, my results indicate that the frog's heart and rabbit's auricle can oxidise phosphoglyceric acid, that the frog's heart can oxidise triosephosphate, but that the rabbit's auricle has little power to oxidise triosephosphate.

The writer gratefully acknowledges his indebtedness to Professor A. J. Clark for his advice and criticism.

The expenses of this research were partly defrayed by a grant from the Moray Research Fund of the University of Edinburgh, for which the writer desires to express his thanks.