Dooku1, an analog of Yoda1, is a selective antagonist of the endogenous Piezo1 channel. Dooku1 inhibited 2 μM Yoda1-induced Ca 2+-entry with IC50 values of 1.3 μM (in HEK 293 cells) and 1.5 μM (in HUVECs). Dooku1 inhibits Yoda1-induced relaxation of aorta.