T. Burdyga, L. Borysova

Department of Cellular and Molecular Physiology,
Institute of Translational Medicine,
University of Liverpool, Crown Street, Liverpool, L69 3BX, UK

2- and 3-dimensional confocal imaging of Fluo-4 loaded ureteric microvesells in situ allowed us to demonstrate distinct morphology, Ca²⁺ signalling and contractility in myocytes of arcade arterioles and pericytes of arcade venules. In myocytes and pericytes, Ca²⁺ signals arise exclusively from Ca²⁺ release from the sarcoplasmic reticulum through inositol 1,4,5-trisphosphate receptors. Са²⁺ transients in pericytes are less oscillatory, slower and longer-lasting than those in myocytes. The data obtained suggest differences in the mechanisms controlling local blood flow in precapillary arterioles and postcapillary venules.