Abstract
The effect of amiloride on responses of the chorda tympani (CT) nerve to NaCl differs among mouse strains. For example, in C57BL mice, amiloride suppresses NaCl responses to about 50% of control, whereas no clear amiloride inhibition was observed in 129 mice. The 129 inbred strain, however, has a number of substrains derived mainly from two major parent stocks, 129/J and 129/SvJ. Recently, 129X1/SvJ (formerly 129/SvJ) mice are reported to differ from the 129P3/J (formerly 129/J) strain by 25% of sequence length polymorphisms. In the current study, therefore, we examined possible substrain difference between 129P3/J and 129X1/SvJ in the amiloride sensitivity of the CT response. The results suggest that amiloride is effective in 129X1/SvJ mice. CT responses to 0.3 M NaCl were significantly suppressed by amiloride at the concentration of 10 µM or more, and the inhibition reached the maximum (about 50% of control to 0.03-0.3 M NaCl) at 100 µM. In contrast, no such amiloride inhibition was evident in 129P3/J mice. These results suggest that amiloride-sensitivity of NaCl responses differ among 129 substrains. [J Physiol Sci. 2006;56 Suppl:S183]
