Fig. 5

Ca²⁺ channel activation in vascular smooth muscle cells. a, b Membrane potential measurements from freshly isolated endothelium of second-order mesenteric arteries. a Example traces from the control and Piezo1^ΔEC genotypes in the absence of Gd³⁺ and the control genotype in the presence of 10 μM Gd³⁺. Endothelium was exposed to flow at 20 μl s⁻¹. b As for a but individual data points for the three independent experiments shown as symbols. Control genotype: no flow −46.3 ± 2.4 mV vs flow −38.4 ± 2.1 mV (***). Control genotype in Gd³⁺: no flow −60.1 ± 3.1 mV vs flow −56.5 ± 3.3 mV (***). Piezo1^ΔEC genotype: no flow −59.5 ± 2.3 mV vs flow −60.7 ± 2.5 mV (*). c As for a, b but a separate series of experiments in which endothelium was exposed to increasing flow in the absence of Gd³⁺ for control (n = 10) and Piezo1^ΔEC (n = 6) genotypes. d Example current recordings from vascular smooth muscle cells (VSMC) freshly isolated from second-order mesenteric artery. Square-step depolarizations were applied at the time of the arrow from a holding voltage of −80 mV to the test voltage indicated. Linear leak and capacitance currents were subtracted. e Mean data for peak VSMC inward currents of the type exemplified in d (current, n = 8). Superimposed in grey are endothelial shear stress values calculated from the control genotype data in c. Membrane potential for the highest shear stress was obtained by extrapolation based on a least-squares fit of the Hill equation. Averaged data are displayed as mean ± s.e.m. Data sets are compared by t-test. Statistical significance is indicated by ***P < 0.001