Epithelial responses to glycinamide and glycylglycinamide in the frog (Rana catesbeiana) tongue.

1. Open-circuit potential difference and short-circuit current across the frog tongue epithelium in response to glycinamide and glycylglycinamide were investigated. 2. Response to both of these amides were larger than the responses produced by glycine, glycylglycine and NaCl, and were independent of Na+ in the mucosal medium but dependent on H+ in the stimulus. 3. The relationships of the magnitudes of both response to the stimulus were similar to that in the taste nerve. 4. The results indicate that H+-dependent transport of these amides is related to taste reception in frogs.