Amiloride inhibition of chorda tympani responses to NaCl and its temperature dependency in mice.

Inhibitory effects of amiloride on salt responses of the chorda tympani nerve and its temperature dependency were compared among three inbred strains of mice (C57BL, BALB and 129). In C57BL mice, lingual treatment with amiloride significantly suppressed responses to 0.1-1.0 M NaCl at two different temperatures, 24 +/- 2 degrees C and 12 +/- 2 degrees C. The magnitude of the amiloride-inhibited component of NaCl response was slightly larger at the higher temperature. In contrast, in BALB mice, amiloride suppression of NaCl responses was observed only at the lower temperature. No such suppression was exhibited by 129 mice at either temperature levels. These results suggest that there exist at least two different amiloride-sensitive receptor components for NaCl in mice: one is more sensitive to NaCl at the higher temperature, and the other is more sensitive at the lower temperature. It is hypothesized, C57BL mice possess the former (or both) component(s), whereas BALB mice have the latter one. The 129 strain may be lacking both components.