Journal: Cells

Article Title: Case Report on: Very Early Afterdepolarizations in HiPSC-Cardiomyocytes—An Artifact by Big Conductance Calcium Activated Potassium Current (I bk,Ca )

doi: 10.3390/cells9010253

Figure Lengend Snippet: Outward currents in C25 human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and the effect of iberiotoxin (IBTX). ( A ) Original outward traces before (black) and after (green) exposure of 100 nM IBTX in insensitive (upper, black directly underlying green curve) and sensitive (lower panel) hiPSC-CMs. ( B – D ). Summary of IBTX (100 nM) effects in insensitive (left panel) and sensitive (right panel) hiPSC-CMs quantified by area under the curve ( B ), peak current ( C ) and current at the end of the test pulse (late current, D ). Mean values ± SEM. * p < 0.05, unpaired Student’s t test for basal values in insensitive vs. sensitive hiPSC-CMs; ## p < 0.01, ### p < 0.001; paired Student’s t test for basal vs. IBTX; n = number of isolated cells/number of individual differentiation batches.

Article Snippet: All drugs and chemicals were obtained from Sigma-Aldrich (St. Louis, MI, USA) except for iberiotoxin (IBTX, Tocris Bioscience, Bristol, UK).

Techniques: Derivative Assay, Isolation

Journal: Cells

Article Title: Case Report on: Very Early Afterdepolarizations in HiPSC-Cardiomyocytes—An Artifact by Big Conductance Calcium Activated Potassium Current (I bk,Ca )

doi: 10.3390/cells9010253

Figure Lengend Snippet: Effects of iberiotoxin (IBTX) on action potentials (APs) in C25 engineered heart tissue (EHT) and in human left ventricular tissue (LV). Original AP recordings before and after exposure to IBTX (100 nM, green) in EHTs with ( A ) and without ( B ) notch/oscillations from cell line C25 and in LV ( C ). Mean values of AP duration at different levels of repolarization (APD 10-90 ) before and after exposure to IBTX (100 nM) in EHTs with ( D ) and without ( E ) notch in cell line C25 and in LV ( F ). Mean values ± SEM, * p < 0.05, ** p < 0.01, paired Student’s t test.

Article Snippet: All drugs and chemicals were obtained from Sigma-Aldrich (St. Louis, MI, USA) except for iberiotoxin (IBTX, Tocris Bioscience, Bristol, UK).

Techniques:

Journal:

Article Title: O 2 sensing is preserved in mice lacking the gp91 phox subunit of NADPH oxidase

doi:

Figure Lengend Snippet: EM and IK are similar in resistance PASMCs from wild-type and CGD mice (A) Resting EM is similar in wild-type (filled bar) and CGD (empty bar) PASMCs. (B) Normoxic current density is similar in wild-type and CGD PASMCs. (C and D) In PASMCs from CGD mice, 4-AP, a Kv channel inhibitor, reduces IK at negative potentials (−10 mV, C, ∗, P < 0.05). Tetraethylammonium (TEA) inhibits IK only at positive potentials, where KCa channels are active (∗, P < 0.05, D). (E and F) Four minutes of acute hypoxia inhibits IK (n = 4 cells/group, ∗, P < 0.01). (G and H) In separate experiments, 4 min of acute hypoxia inhibits IK even after specifically inhibiting large conductance KCa channels with IBTX. This finding suggests the hypoxia-sensitive current is at least partially Kv current (†, ∗ P < 0.05 IBTX and hypoxia inhibit IK, respectively).

Article Snippet: All drugs were from Sigma except IBTX (Peptides International) and DPI (Research Biochemicals, Natick, MA).

Techniques: