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. 2011 Oct 27;93(2):252–262. doi: 10.1093/cvr/cvr283

Figure 2.

Figure 2

Repolarizing K+ current amplitudes are increased and K+ current densities are normalized in caPI3Kα + TAC LV myocytes. (A) Representative whole-cell K+ currents recorded from myocytes isolated from the LV apex of caPI3Kα control and caPI3Kα + TAC mice. Currents were evoked in response to (4.5 s) voltage steps to test potentials between −120 and +40 mV from a holding potential (HP) of −70 mV. (B) The mean ± SEM amplitudes of the K+ currents are significantly (‡P < 0.05, #P < 0.01,*P < 0.001) higher in caPI3Kα + TAC, compared with caPI3Kα control, LV myocytes. (C) A significant (#P < 0.01) increase in mean ± SEM whole-cell membrane capacitance (Cm), consistent with cellular hypertrophy, is also evident in caPI3K + TAC LV myocytes. (D) Normalizing current amplitudes for differences in cell size (Cm) revealed that mean ± SEM K+ current densities in LV myocytes from caPI3Kα + TAC and caPI3Kα control animals are indistinguishable. Inset: as reported previously,6 IK,peak, Ito,f, IK,slow, and IK1 amplitudes are not increased in WT LV myocytes with TAC and current densities are decreased significantly (‡P < 0.05, #P < 0.01).