title: Estimation of the number of angiotensin II AT1 receptors in rat kidney afferent and efferent arterioles.
abstract: OBJECTIVE
  To examine the effects of the renin-angiotensin system (RAS) on renal arterioles to determine the association between the distribution of angiotensin II AT1 receptors and the morphologic and physiologic heterogeneity of renal arterioles.
  
  
  METHODS
  To estimate the number of angiotensin II AT1 receptors along the length of the arterioles and per arteriole, we combined immunoelectron microscopy with stereology.
  
  
  RESULTS
  The number of AT1 receptor molecules was significantly lower in the renin-positive smooth muscle cells (SMCs) than in the renin-negative SMCs of the afferent and efferent arterioles. There were no significant differences along and between the afferent and efferent arterioles in relative number of AT1 receptors of endothelial cells or SMCs.
  
  
  CONCLUSIONS
  Our results suggest that the heterogeneous activity of angiotensin II in SMCs and the different permeabilities of the endothelium along the afferent arterioles are probably not controlled directly by angiotensin II AT1 receptors. However, the activity of the RAS is possibly involved in the significantly reduced number of receptors in renin-granulated cells. An understanding of how the number of AT1 receptors on the SMC surface is controlled may furnish a new path for pharmacologically changing RAS activity on SMCs.
authors: Stereology and Electron Microscopy Research Laboratory and MIND Center, University of Aarhus, Aarhus, Denmark. razgazst@patho.szote.u-szeged.hu
authors: Zsolt
authors: Z
authors: Razga
authors: Jens Randel
authors: JR
authors: Nyengaard
mesh_terms: D000344:Afferent Pathways / Q000378:metabolism; D000818:Animals; D001160:Arterioles / Q000378:metabolism / Q000648:ultrastructure; D004525:Efferent Pathways / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D017979:Gold Colloid; D007606:Juxtaglomerular Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D007678:Kidney Glomerulus / Q000098:blood supply* / Q000648:ultrastructure; D008297:Male; D016253:Microscopy, Immunoelectron; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism* / Q000648:ultrastructure; D012084:Renin-Angiotensin System / Q000502:physiology*; D013194:Staining and Labeling
chemical_list: D017979:Gold Colloid; D044140:Receptor, Angiotensin, Type 1