Chloroform responses of the chorda tympani nerve in the rat

Abstract

Electrophysiological analysis of the chorda tympani nerve response to saturated chloroform solution was performed in the rat, and the results were compared to those of the sucrose response. The chloroform response was characterized by a transient response, and it lacked an off-type response to the water rinse of the tongue. Treatment of the tongue with 0.1 M anionic detergent and 5 × 10 −4 M HgCl 2 produced the same effects on the chloroform and sucrose responses. However, the effects of some metallic ions on response to chloroform were different from those on the sucrose response. That is, 0.1 M CaCl 2 suppressed the chloroform response and the off-type response, but 0.001 M CuCl 2 suppressed only the sucrose response. Additive effect of sucrose and chloroform was rather smaller than the summation expected by doubling of the responses of sucrose and chloroform. The fibers which showed the off-type discharges also always responded to chloroform. These results suggest that sucrose and chloroform combine to the different loci within the same taste receptor macromolecule.