Red blood cell Much of this potential appears to be contributed by the exposed sialic acid residues in the membrane: their removal results in zeta potential of −6.06 mV. When red blood cells undergo shear stress in constricted vessels, they release ATP, which causes the vessel walls to relax and dilate so as to promote normal blood flow. When their hemoglobin molecules are deoxygenated, red blood cells release S-nitrosothiols, which also act to dilate blood vessels, thus directing more blood to areas of the body depleted of oxygen. Red blood cells can also synthesize nitric oxide enzymatically, using L-arginine as substrate, as do
U2 Live at Red Rocks: Under a Blood Red Sky U2 Live at Red Rocks: Under a Blood Red Sky U2 Live at Red Rocks: Under a Blood Red Sky is a concert film by Irish rock band U2. It was recorded on 5 June 1983 at Red Rocks Amphitheatre in Colorado, United States, on the group's War Tour. Originally released in 1984 on videocassette, "U2 Live at Red Rocks" was the band's first video release. It accompanied a 1983 live album entitled "Under a Blood Red Sky", on which two tracks from the film appear. The video was directed by Gavin Taylor and produced by Rick Wurpel and Doug