Background: This contribution deals with chemical processes at the biological membranes of endothelial cells in blood vessels. A basic observation is that the intensity of blood flow navigates the vascular width through a negative feedback circle. When the blood flow increases, the vessels become wider; when it decreases the vascular smooth muscle cells contract. The anionic polyelectrolyte heparan sulfate proteoglycan (HS-PG) reacts to the shear stress generated by the flowing blood. In the present investigation, this naturally occurring biosensor is characterized in more detail, which is crucially involved in the regulation of peripheral blood flow and organ perfusion. A dysfunction of this sensor can lead to organ insufficiency, hypertension and arteriosclerosis.
