Salt taste responses of mouse chorda tympani neurons: evidence for existence of two different amiloride-sensitive receptor components for NaCl with different temperature dependencies.

1. Inhibitory effects of amiloride on salt responses of single fibers of the chorda tympani nerve of the C57BL/6 strain of mice were examined at two different temperatures (approximately 12 and 24 degrees C). 2. Of 36 single fibers that responded to NaCl, 20 fibers showed strong suppression of responses to NaCl actuated by lingual treatment with amiloride (amiloride-sensitive fibers), whereas the remaining 16 fibers showed no such amiloride inhibition (amiloride-insensitive fibers). 3. Twenty amiloride-sensitive fibers were further classified into two subgroups according to the temperature dependency of their NaCl responses. In 15 of 20 fibers, amiloride-inhibitable NaCl responses were larger at 24 degrees C than at 12 degrees C, whereas the reverse was true for the remaining 5 fibers. All amiloride-insensitive fibers showed smaller responses to NaCl at 12 degrees C. 4. These results suggest that there exist two different amiloride-sensitive receptor components for NaCl with different temperature dependencies in mouse taste cells: one is more sensitive to NaCl at the higher temperature, and the other is more sensitive at the lower temperature.