Frog atrial natriuretic peptide and cGMP activate amiloride-sensitive Na+ channels in urinary bladder cells of Japanese tree frog, Hyla japonica

摘要: In our previous study, it was suggested that ANP and cGMP may increase Na+ absorption in the urinary bladder of Japanese tree frog, Hyla japonica. Thus, transport activated by investigated electrophysiologically using a cell-attached patch-clamp technique freshly isolated cells from bladder. A predominant channel expressed low conductance epithelial cells. The exhibited for inward currents 4.9 ± 0.2 pS, long open closed times (c.a. 190 ms), positive reversal potential. activity decreased under pipette solution including 10−6 M amiloride. These characteristics were similar to those amiloride-sensitive channels (ENaC). Addition 10−9 significantly increased ENaC 0.58 0.09 1.47 0.34. On other hand, mean amplitudes single did not change after addition ANP. 10−5 8-Br-cGMP also 0.56 0.10 2.00 0.33. failed activate presence results via frog