Mechanical stretch preferentially activated a heterotrimeric G protein-independent AT1 signaling pathway.

<p>(<b>A</b>) In vitro cultured cardiomyocytes were seeded on 24 well plates (1.5×10⁵ cells) and labeled by myo-[³H] inositol (1.0 µCi/mL) at 37°C for 24 h. Inositol phosphates (IPx) release was determined at the different indicated time points triggered by AngII (10⁻⁷ mol/L) or stretch respectively, and including the treatment of candesartan. (<b>B</b>) The effect of GF109203X on ERK1/2 phosphorylation stimulated by stretch or AngII (10⁻⁷ mol/L). (<b>C</b>) The endogenous mRNA and protein levels of β-arrestin1 and β-arrestin2 in cardiomyocytes were determined before and after stretch for 10 min. (<b>D</b>) Time-dependent ERK1/2 phosphorylation was determined after treatment with β-arrestin1/2 siRNA or scrambled siRNA. (<b>E</b>) Mechanical stretch-induced expression of phosphorylated ERK1/2 was determined in a single plasmid (β-arrestin1 or β-arrestin2) transfected HEK-293-AT1 cells after knock-down of endogenous β-arrestin1/2. * <i>P</i><0.05 vs. AngII-induced group (n = 3 separated experiments).