Fig. 4. Potentiation of native coronary Kv1 activity by NADH requires Kvβ2.

A, B Unitary K⁺ channel currents (-80-80 mV as indicated, left) and summarized I-V relationships (right) from inside-out patch recordings from isolated coronary arterial myocytes (wild type 129SvEv, A) or Cos-7 cells transiently expressing Kv1.5 (B). (A) n = 6 cells; (B) n = 4 cells. C Single K⁺ channel activity in patches from coronary arterial myocytes at a holding potential of +40 mV in the absence and presence of psora-4 (500 nM). D Summary of K⁺ channel open probabilities (nPo, mean values ± SEM) recorded in the absence and presence of 500 nM psora-4. n = 6 cells, *p = 0.0312 (two-sided Wilcoxon matched-pairs signed rank test). E Representative single Kv current recordings (holding potential = −40 mV) in the absence (ct) and presence of 1 mM NADH (top) or 1 mM NAD⁺ (bottom). F Summary of Kv channel nPo (mean values ± SEM) recorded before (ct) and after bath application of 1 mM NADH (n = 27 cells) or NAD⁺ (n = 15 cells). **p = 0.0076 (paired two-sided t test). G Single Kv channel currents recorded from freshly isolated human coronary arterial myocyte membrane patches before and after application of 1 mM NADH. nPo values for each condition are provided above each set of example traces. Data are representative of four independent experiments (one donor). H Inside-out patch recordings in coronary arterial myocyte membrane patches from Kvβ1.1^−/− or Kvβ2^−/− mice before and after application of 1 mM NADH. I Summary of fold-change in nPo (NADH:ct; mean values ± SEM) in patches from wild type (n = 26 cells from 8 mice), Kvβ1.1^−/− (n = 23 cells from 8 mice), and Kvβ2^−/− mice (n = 19 cells from 6 mice). *p = 0.0115 (Brown-Forsythe ANOVA with Dunnett’s multiple comparisons test of log-transformed data). Source data are provided as a Source Data file.