CHANGES IN PHYSIOLOGICAL-PROPERTIES OF FROG TASTE CELLS FOLLOWING DENERVATION

The structure of the taste organ and the physiological properties of the taste cell of the bullfrog (Rana catesbeiana) after the glossopharyngeal nerve transection were investigated. The frog taste organ is composed of taste, supporting and basal cells. As nerve terminals within the taste organ degenerated, nerve responses to mechanical, chemical and electrical stimuli gradually declined and finally ceased in similar to 7 days during the summer and 15 days during the winter. However, the taste cells still had resting potentials and responded to four basic taste stimuli by generating receptor potentials with the various lengths of duration, even 140 days after denervation. The glossopharyngeal nerve transection affected the magnitude of resting potentials significantly. However, the taste, supporting and basal cells maintained their normal structures 140 days after surgery. It is concluded, therefore, that neural dependency of the frog taste organ is not as great as that in mammals.