title: Serotonin and haemorrheology.
abstract: One of the crucial determinants of tissue perfusion is the flow behaviour, that is the rheology, of the blood itself. In the microcirculation the most important factor is the ability of the cellular components of blood to deform as they pass through the narrower capillary passages. Until recently, it was thought that the deformability of the red cells was more important than that of the white cells, because of their numerical superiority. Recently, the flow behaviour of white cells is thought to be at least equally important. There is now extensive epidemiological, experimental and clinical evidence linking the microrheological properties of blood to tissue ischaemia. The possible role of serotonin in altering haemorrheology is inferred from studies using specific serotonin antagonists. Ketanserin, given orally has been shown to improve blood filterability in patients with myocardial infarction and intermittent claudication. There was also a specific effect on white cells. It is postulated on the basis of these and other experiments that in situations of tissue ischaemia, when there is a local increase in plasma serotonin levels, the deleterious effect of serotonin on blood cell rheology may have an important role in perpetuating the ischaemia.
mesh_terms: D001809:Blood Viscosity / Q000187:drug effects; D002199:Capillary Permeability / Q000187:drug effects; D004907:Erythrocyte Deformability / Q000187:drug effects; D006801:Humans; D007511:Ischemia / Q000188:drug therapy / Q000503:physiopathology; D007650:Ketanserin / Q000494:pharmacology / Q000627:therapeutic use*; D007962:Leukocytes / Q000187:drug effects; D008833:Microcirculation / Q000187:drug effects; D012212:Rheology; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D012702:Serotonin Antagonists; D012701:Serotonin; D007650:Ketanserin