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. Author manuscript; available in PMC: 2019 Dec 3.
Published in final edited form as: Pflugers Arch. 2017 Dec 27;470(4):599–611. doi: 10.1007/s00424-017-2099-3

Figure 6. Kir2.1•E224G channels maintain one stable level of resting membrane potential in human iPSC-derived cardiomyocytes.

Figure 6.

(A-B) Resting membrane potentials (top and/or middle) and whole-cell ramp currents (bottom) of human iPSC-derived cardiomyocytes that over-express (A) Kir2.1 or (B) inward rectification-deficient Kir2.1•E224G mutant channels before and after [K+]e was reversibly changed from 5.4 mM to 2 mM. Blue numbers indicate phases 1 and 2 of changes in resting membrane potential. Time scale, 100 s. Black line indicates whole-cell ramp currents recorded in 5.4 mM [K+]e, and pink lines indicate currents recorded in 2 mM [K+]e. Blue and green lines indicate “b” and “c” types of currents, respectively, whereas pink line indicates “a” type N-shaped current with three zero-current potentials. (C) The percentages of human iPSC-derived cardiomyocytes that express Kir2.1 (black bar) or Kir2.1•E224G (purple bar), which show two levels of resting membrane potential in 2 mM [K+]e (* P < 0.001, n = 53 to 160 cells).