Figure 6. Phenotype of BKβ1^−/− strain C mice.

Strain C is an inbred C57BL/6J × strain A hybrid strain. For experimental details see Methods. A, telemetric recordings of mean arterial pressure (MAP). B, aortic tone under maximal α₁-adrenergic stimulation (100 μmol l⁻¹ PE). C, heart weight (HW) normalized to body weight (BW). D, plasma aldosterone concentration. E, serum K⁺ concentration. F, serum Na⁺ concentration. n, number of animals. G, BK channel open probabilities in vascular myocytes of BKβ1^−/− mice, BKβ1^+/+ controls and BKβ1 R9 mice backcrossed to strain C. Measurements were performed as described for Fig. 4A. Data points denote open probabilities (P_O) calculated from peak area integrals of current histograms of single channel recordings. Curves denote best free Boltzmann sigmoidal fits (P_O = 1/[1 + e^{([Cai]½ − [Cai])/dCa}] ). Mouse genotypes: +/+, BKβ1^+/+; −/−, BKβ1^−/−; R9, BKβ1 R9. *Statistically significant difference (ANOVA, post hoc: Bonferroni-corrected). Error bars: SEM.