1. ¹Molecular Pharmacology Group, Division of Neuroscience and Molecular Pharmacology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
2. ²Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
3. ³Water and Salt Research Centre, University of Aarhus, Aarhus, Denmark
4. ⁴Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, USA
5. ⁵Department of Pediatrics, Philipps-University of Marburg, Marburg, Germany

Correspondence: Joris H. Robben, 286 Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB, Nijmegen, The Netherlands. E-mail: j.robben@ncmls.ru.nl

Received 16 July 2009; Revised 16 July 2009; Accepted 28 July 2009; Published online 23 September 2009.

Abstract

When the succinate receptor (SUCNR1) is activated in the afferent arterioles of the glomerulus it increases renin release and induces hypertension. To study its location in other nephron segments and its role in kidney function, we performed immunohistochemical analysis and found that SUCNR1 is located in the luminal membrane of macula densa cells of the juxtaglomerular apparatus in close proximity to renin-producing granular cells, the cortical thick ascending limb, and cortical and inner medullary collecting duct cells. In order to study its signaling, SUCNR1 was stably expressed in Madin-Darby Canine Kidney (MDCK) cells, where it localized to the apical membrane. Activation of the cells by succinate caused Gq and Gi-mediated intracellular calcium mobilization, transient phosphorylation of extracellular regulated kinase (ERK)1/2 and the release of arachidonic acid along with prostaglandins E2 and I2. Signaling was desensitized without receptor internalization but rapidly resensitized upon succinate removal. Immunohistochemical evidence of phosphorylated ERK1/2 was found in cortical collecting duct cells of wild type but not SUCNR1 knockout streptozotocin-induced diabetic mice, indicating in vivo relevance. Since urinary succinate concentrations in health and disease are in the activation range of the SUCNR1, this receptor can sense succinate in the luminal fluid. Our study suggests that changes in the luminal succinate concentration may regulate several aspects of renal function.