Release of vasoactive substances from endothelial cells by shear stress and purinergic mechanosensory transduction

The evidence for release of vasoactive substances from endothelial cells in response to shear stress caused by the viscous drag of passing fluids is r eviewed and, in particular, its physiological significance both in shortter m regulation of blood vessel tone and in long-term regulation of cell growt h, differentiation, proliferation, and cell death in pathophysiological con ditions is discussed. A new concept of purinergic mechanosensory transducti on, particularly in relation to nociception, is introduced. It is proposed that distension of tubes (including ureter, vagina, salivary and bile ducts , gut) and sacs (including urinary and gall bladders, and lung) leads to re lease of ATP from the lining epithelium, which then acts on P2X(2/3) recept ors on subepithelial sensory nerves to convey information to the CNS.