Dependence of gustatory neural response on depolarizing and hyperpolarizing receptor potentials of taste cells in the rat.

The rat taste cells responded to the four basic taste stimuli (0.5 M NaCl, 0.02 M quinine-HCl (Q-HCl), 0.01 M HCl and 0.5 M sucrose) with depolarizing or hyperpolarizing receptor potentials. The rates of obtaining hyperpolarizing responses under 41.1 mM NaCl adaptation were 3% for NaCl, 42% for Q-HCl, 21% for HCl and 37% for sucrose. Most of the taste cells responded to more than two kinds of taste stimuli. The ratio of mean magnitudes of depolarizing and hyperpolarizing responses for the four basic taste stimuli under 41.4 mM NaCl was as follows: NaCl:Q-HCl:HCl:sucrose = 100:9:48:2. The ratio of mean magnitudes of tonic chorda tympani nerve responses for the four basic taste stimuli under 41.4 mM NaCl was: NaCl:Q-HCl:HCl:sucrose = 100:5:37:2. Comparison of both taste cell and nerve responses suggests that the depolarization of a taste cell is concerned with a generation of gustatory neural impulses, and that the hyperpolarization is concerned with a depression of the impulses.