Disruption of lipid rafts with MβCD inhibits EC coupling mediated by 5-HT. (A) Mean cumulative dose–response curves to 5-HT in mouse pulmonary arteries from wild-type C57/BL6 mice in control condition (black circles, Control; N = 14), a 10-min exposure to 10 μM CPA (blue squares; N = 4), a 10-min exposure to 10 μM CaCC_Inh-A01 (blue circles; N = 6), or after a 30-min incubation with MβCD (3 mg/ml) to deplete membrane cholesterol and disrupt lipid rafts (upper triangles; N = 5). The data for the control, CPA, and CaCC_Inh-A01 groups were reproduced from Fig. 1 B to facilitate comparisons. Each data point is a mean ± SEM of net contractile force normalized to the second high K⁺–Krebs solution-induced contraction (see description in Materials and methods). (B–E) The summarized data presented in B–E show the effects of exposure of pulmonary arteries from conditional and smooth muscle-specific GCaMP6f mice (SMC-GCaMP6f) to a 30-min exposure with 3 mg/ml of MβCD on the frequency of GCaMP6f Ca²⁺ oscillations (B; Control, n = 58; MβCD, n = 78), peak GCaMP6f Ca²⁺ transients (C; Control, n = 58; MβCD, n = 70), area under the curve of GCaMP6f Ca²⁺ transients (D; Control, n = 58; MβCD, n = 70) and FWHM GCaMP6f Ca²⁺ transients (E; Control, n = 58; MβCD, n = 70). The Control (light blue boxes) and MβCD (light gray boxes) datasets in B–F are from the same animals (N = 4). For each dataset in the latter panels, the mean is indicated by a filled black square with the colored boxes and whiskers delimiting the 25th and 75th percentile, and the 10th and 90th percentile of the pooled data, respectively, and small dots individual data points. For all panels, *** indicates a significant difference between means with P < 0.001.