Sugar-evoked potential in isolated toad intestine.

fluid having contained no sugar or amino acid initially causes animmediate rapid increase of the mucosal negativity.Although the properties of this potential increment(the sugar-or the amino acid-evoked potential)have been studied in various animal species by different authors,20-11,14)the nature of its genesis has not yet been fully explained. As shown by several authors,20-11,14)the sugar-or the amino acid-evoked potential is a phenomenon directly associated with the sodium-sugar or the sodium-amino acid interaction in the mucosal epithelial cells .Therefore,knowledge concerning its genesis seems to be of great importance for elucidating the sodium dependent active transport of nonelectrolytes by the intestine and some other tissues.This led us to an investigation on the nature of this potential.In our series of experiments,small intestines isolated from hibernating toads were employed because they exhibited quite stable sugar-evoked potentials.In the present study,the effects of different sugars on the transmural potential and the effects on the sugar-evoked potential of phlorizin and various external conditions were studied in order to see the characteristics of this particular potential exhibited by the toad intenstine.