Table 3

Relative macroscopic amiloride-sensitive currents with divalent cations at −100 mV

IMg/INaICa/INaISr/INaIBa/INa
αS589A0.00  ±  0.00−0.01  ±  0.01−0.01  ±  0.00*−0.01  ±  0.00
αS589C0.00  ±  0.00*0.00  ±  0.000.01  ±  0.00*0.00  ±  0.00
αS589D−0.01  ±  0.010.06  ±  0.01*0.05  ±  0.01*0.03  ±  0.00*
wt−0.02  ±  0.00−0.01  ±  0.02−0.02  ±  0.00−0.01  ±  0.00
  • Amiloride-sensitive currents carried by divalent cations relative to INa are shown. All data are from experiments carried out with oocytes that had been injected with a BAPTA solution before the experiment (see Methods) to chelate intracellular Ca2+. Data are from 4-11 oocytes from 3-4 different batches per condition. ∗, different from wt (P < 0.01). Negative current ratios indicate that at −100 mV an outward current was measured with the divalent cation. INa at −100 mV was 31.7 ± 20.0 μA for wt, 12.2 ± 17.7 μA for αS589A, 3.2 ± 1.7 μA for αS589C, and 5.9 ± 2.0 μA for the αS589D mutant.