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BioMed Research International
Volume 2014 (2014), Article ID 947506, 6 pages
http://dx.doi.org/10.1155/2014/947506
Research Article

Heterogeneous Downregulation of Angiotensin II AT1-A and AT1-B Receptors in Arterioles in STZ-Induced Diabetic Rat Kidneys

1Department of Pathology, University of Szeged, Hungary
2Department of Pediatrics, University of Szeged, Állomás Utca 2, Szeged 6725, Hungary
3Department of Physiology, Anatomy and Neuroscience, University of Szeged, Hungary
4Electron Microscopy and Stereology Research Laboratory, University of Aarhus, Denmark

Received 3 April 2013; Revised 1 August 2013; Accepted 31 October 2013; Published 21 January 2014

Academic Editor: Richard Tucker

Copyright © 2014 Zsolt Razga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Introduction. The renin granulation of kidney arterioles is enhanced in diabetes despite the fact that the level of angiotensin II in the diabetic kidney is elevated. Therefore, the number of angiotensin II AT1-A and AT1-B receptors in afferent and efferent arteriole’s renin-positive and renin-negative smooth muscle cells (SMC) was estimated. Method. Immunohistochemistry at the electron microscopic level was combined with 3D stereological sampling techniques. Results. In diabetes the enhanced downregulation of AT1-B receptors in the renin-positive than in the renin-negative SMCs in both arterioles was resulted: the significant difference in the number of AT1 (AT1-A + AT1-B) receptors between the two types of SMCs in the normal rats was further increased in diabetes and in contrast with the significant difference observed between the afferent and efferent arterioles in the normal animals, there was no such difference in diabetes. Conclusions. The enhanced downregulation of the AT1-B receptors in the renin-negative SMCs in the efferent arterioles demonstrates that the regulation of the glomerular filtration rate by the pre- and postglomerular arterioles is changed in diabetes. The enhanced downregulation of the AT1-B receptors in the renin-positive SMCs in the arterioles may result in an enhanced level of renin granulation in the arterioles.