Fig. 4: Functional and molecular VGCC phenotyping.

Potassium concentration-response curves of 5- and 26-month-old mice were plotted in the absence (circles) and presence (squares) of L-NAME (a). Non-linear regression analysis was used to calculate the maximal effect (b) and EC₅₀ value (c). 50 mM potassium-induced contraction-dependent change in Peterson modulus at calculated isobaric 80–120 mmHg distending pressure was measured in the absence and presence of 300 µM L-NAME (d). Splice variation was assessed for CaV1.2 exon 9* and exon 33, and quantification of the % mRNA with inclusion of exon 9* or exon 33 is shown (e). The fraction nuclear/total myocardin in the media was assessed using immunohistochemical staining, as a marker of VSMC phenotype regulation (f). Data are listed as mean ± SEM (a, e, n > 5) or each symbol represents an individual biological repeat (b–d, f, n > 5). Statistical analysis using three-way ANOVA (a), two-way ANOVA (b–d), or one-way ANOVA (e, f). Overall significance (bottom of graph) and post hoc significance vs. 4-month value (in graph) are listed (post hoc significance was not added in a). **p < 0.01, ***p < 0.001. In c, d, post hoc comparison for L-NAME effect is listed as ^#p < 0.05.