Activation of human TRPV2-like channel currents in human umbilical vein endothelial cells (HUVEC). Activation of the channel was monitored as an increase in Ca²⁺ fluorescence signal in the cell. (A) In the perfusion of a bathing solution with Ca²⁺ (a linear line) and without Ca²⁺ (a dotted line); 70 percent hypoosmotic stress (227 mOsm) was applied. (B) The 70 percent hypoosmotic stress-induced Ca²⁺ fluorescence change was markedly inhibited by 1 and 3 μM ruthenium red (RuR). (C) A slight but substantial increase in Ca²⁺ fluorescence signal (delta ratio) was evident when 4αPDD was present in the bathing solution. As control experiments, 10 μM ATP (shaded column) and 70 percent hypoosmotic solution (solid column) were applied. (D) A modest (20–46°C, open squares) and high (20–60°C, closed circles) heat-evoked change in Ca²⁺ fluorescence signal was plotted against temperature in the bathing solution. (E) Distribution of human type TRPV2, TRPV4a, TRPV4b, and GAPDH mRNA transcripts in HUVEC, HEK293, human heart, and human brain using PCR amplification (35 cycles).