Erythrocytes as regulators of blood vessel tone

A drop in oxygen partial pressure results in elevation of blood vessel diameter. It has been demonstrated that isolated vessels exhibit this unique feature only when they are perfused in the presence of erythrocytes. More recently, it was shown that haemoglobin plays a key role in oxygen sensing. Its deoxygenated form interacts with band 3 protein, triggering the cascade of non-identified intracellular signals involved in nitric oxide production and release of ATP interacting with P2Y purinergic receptors in endothelial cells. In this review, we summarize the data on mechanisms of ATP release from erythrocytes, as well as on its physiological and pathophysiological implications