The dual roles of red blood cells in tissue oxygen delivery: oxygen carriers and regulators of local blood flow
Jensen, 2009
This is an interesting paper. Among other things:
So red blood cells release ATP when they sense hypoxic tissues (this occurs during exercise when muscles require more oxygen) but also apparently when they are mechanically deformed (squeezed). That released ATP activates the synthesis of vasodilators including nitric oxide which then increase the size of blood vessels so more blood can flow.
Jensen, 2009
This is an interesting paper. Among other things:
Mammalian RBCs release ATP when exposed to reduced oxygen tensions, and the amount released is linked to the decrease in Hb O2 saturation (Ellsworth et al., 1995; Jagger et al., 2001). The extracellular ATP diffuses to the endothelium, where it binds to P2y purinergic receptors, which activates the synthesis of vasodilators (including nitric oxide) that relax vascular smooth muscles and increase local blood flow and O2 delivery (Ellsworth et al., 1995; Sprague et al., 2007). The local extracellular concentration of ATP in hypoxic tissue regions is in the 10–6 mol l–1 range, and ATP is clearly capable of inducing vasodilation at such concentrations (Ellsworth, 2000).
ATP release is activated not only by PO2 decrease but also by mechanical deformation (Sprague et al., 2001), as would occur when RBCs are squeezed through narrow vessels.
So red blood cells release ATP when they sense hypoxic tissues (this occurs during exercise when muscles require more oxygen) but also apparently when they are mechanically deformed (squeezed). That released ATP activates the synthesis of vasodilators including nitric oxide which then increase the size of blood vessels so more blood can flow.
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