Effects of gustatory stimulants upon the olfactory epithelium of the bullfrog and the carp

Effects of various gustatory stimulants upon the olfactory spithelia were examined in the olfactory bulb of the bullfrog and the carp. 1. The olfactory epithelia of the two animals responded to the salty, bitter- and acid-tasting substances, but not to the sweet ones. 2. The olfactory epithelium of the bullfrog responded immediately to sodium solutions of high concentrations (the "initial response"), but the response to those of low concentrations showed long latency (the "delayed response"). In the carp, the "initial response" was found, while the "delayed response" was not in most cases. A "negative" delayed response was found only infrequently. 3. Responses only to high alkali or acid solutions were found in the two animals. 4. When 0.05 M NaCl was added to HCl solutions, an enhancing effect was found in the bullfrog, while a reducing effect occurred in the carp. On the contrary, when 0.05 M NaCl was added to NaOH solutions, an enhancing effect occurred in the carp, while no consistent result was founding the bullfrog. 5. Many amino acids were effective stimuli in the bullfrog, but only betaine and 1-aspartic acid were found effective in the carp. 6. Changes in temperatures beyond 35 degrees C or under 10 degrees C elicited responses. Mechanical stimuli were effective in the carp, but not in the bullfrog. 7. The "water response" was found in the bullfrog, but not in the carp. 8. Sensitivities of the olfactory epithelia of the two animals were compared and discussed.