Biomaterial Database

Estimation of the number of angiotensin II AT1 receptors in rat kidney afferent and efferent arterioles. 2007

Zsolt Razga, and Jens Randel Nyengaard

Stereology and Electron Microscopy Research Laboratory and MIND Center, University of Aarhus, Aarhus, Denmark. razgazst@patho.szote.u-szeged.hu

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.

UI	MeSH Term	Description	Entries
D007606	Juxtaglomerular Apparatus	A complex of cells consisting of juxtaglomerular cells, extraglomerular mesangium lacis cells, the macula densa of the distal convoluted tubule, and granular epithelial peripolar cells. Juxtaglomerular cells are modified SMOOTH MUSCLE CELLS found in the walls of afferent glomerular arterioles and sometimes the efferent arterioles. Extraglomerular mesangium lacis cells are located in the angle between the afferent and efferent glomerular arterioles. Granular epithelial peripolar cells are located at the angle of reflection of the parietal to visceral angle of the renal corpuscle.	Apparatus, Juxtaglomerular
D007678	Kidney Glomerulus	A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.	Glomerulus, Kidney
D008297	Male		Males
D012084	Renin-Angiotensin System	A BLOOD PRESSURE regulating system of interacting components that include RENIN; ANGIOTENSINOGEN; ANGIOTENSIN CONVERTING ENZYME; ANGIOTENSIN I; ANGIOTENSIN II; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming ANGIOTENSIN I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to ANGIOTENSIN II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal VASCULAR SMOOTH MUSCLE, leading to retention of salt and water in the KIDNEY and increased arterial blood pressure. In addition, angiotensin II stimulates the release of ALDOSTERONE from the ADRENAL CORTEX, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down BRADYKININ, a powerful vasodilator and component of the KALLIKREIN-KININ SYSTEM.	Renin-Angiotensin-Aldosterone System,Renin Angiotensin Aldosterone System,Renin Angiotensin System,System, Renin-Angiotensin,System, Renin-Angiotensin-Aldosterone
D004525	Efferent Pathways	Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.	Motor Pathways,Efferent Pathway,Pathway, Efferent,Pathways, Efferent
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001160	Arterioles	The smallest divisions of the arteries located between the muscular arteries and the capillaries.	Arteriole
D013194	Staining and Labeling	The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.	Histological Labeling,Staining,Histological Labelings,Labeling and Staining,Labeling, Histological,Labelings, Histological,Stainings
D016253	Microscopy, Immunoelectron	Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.	Immunoelectron Microscopy,Microscopy, Immuno-Electron,Immuno-Electron Microscopies,Immuno-Electron Microscopy,Immunoelectron Microscopies,Microscopies, Immuno-Electron,Microscopies, Immunoelectron,Microscopy, Immuno Electron