Figure 2.

Endothelial cell morphology and number measurements from excised vessel segments. A: Time-lapse fluorescent intensity images show relative Ca²⁺ fluorescence in fields of intact endothelium. Endothelial cell morphology is revealed through preparing pulmonary artery segments en face, loading with the fluorescent Ca²⁺ indicator dye, Fluo-4, and measuring basal cell Ca²⁺ dynamics for 3 minutes. Wild-type (wt), normotensive endothelial cells are elliptical, in contrast to severely hypertensive [pulmonary arterial hypertension (PAH)] wild-type rats, who exhibit a polygonal appearance. Normotensive rats genetically lacking TRPC4 (ko) exhibit endothelium, a slightly round appearance compared with wt, and endothelial cells of ko rats with severe hypertension are markedly larger and more elliptical than cells in wt PAH rats. B: Endothelial cells in each 133 × 133-μm field were counted for each replicate. There is no significant difference in endothelial cell number for PAH or TRPC4-knockout groups. n = 4 for all groups (B).