AMILORIDE INHIBITION OF CHORDA TYMPANI RESPONSES TO NACL AND ITS TEMPERATURE DEPENDENCY IN MICE

Inhibitory effects of amiloride on salt responses of the chorda tympan i nerve and its temperature dependency were compared among three inbre d strains of mice (C57BL, BALB and 129). In C57BL mice, lingual treatm ent with amiloride significantly suppressed responses to 0.1-1.0 M NaC l at two different temperatures, 24 +/- 2 degrees C and 12 +/- 2 degre es C. The magnitude of the amiloride-inhibited component of NaCl respo nse was slightly larger at the higher temperature. In contrast, in BAL B mice, amiloride suppression of NaCl responses was observed only at t he 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 i n mice: one is more sensitive to NaCl at the higher temperature, and t he other is more sensitive at the lower temperature. It is hypothesize d, C57BL mice possess the former (or both) component(s), whereas BALB mice have the latter one. The 129 strain may be lacking both component s.