Biomaterial Database

Histochemical localization of NADPH-dependent diaphorase (nitric oxide synthase) activity in vascular endothelial cells in the rat brain. 1993

P L Gabbott, and S J Bacon

University Department of Pharmacology, Oxford, U.K.

This study investigated the localization of NADPH-dependent diaphorase activity within vascular endothelial cells in the rat brain. Light microscope observations showed that in addition to neurons and neuronal processes stained histochemically for NADPH-dependent diaphorase activity, endothelial cells in many medium to large diameter (20-100 microns) blood vessels were also stained. These vessels were either attached to the pial surface or contained within the substance of the tissue. In vascular endothelia, the formazan end-product of the diaphorase reaction was deposited as discrete clusters of darkly stained punctae that were located around the nucleus of these cells. Correlated light- and electron-microscopical examination revealed that the sites of formazan deposition occurred in regions of endothelial cytoplasm devoid of smooth and rough endoplasmic reticulum and of mitochondria. Since endothelial NADPH dependent diaphorase activity co-localizes with the activity of nitric oxide synthase (the synthetic enzyme for nitric oxide) these observations suggest that in vascular endothelial cells nitric oxide synthase may be a highly localized soluble cytosolic enzyme not structurally associated with any subcellular organelle. In addition, specific regions of the smooth muscle cells encircling the larger diameter blood vessels clearly demonstrated NADPH dependent diaphorase activity. Unmyelinated fibres and fibre-plexi surrounding blood vessels on the pial surface were also stained. The results of this study show specific NADPH dependent diaphorase activity in vascular endothelial cells in the rat brain. Therefore, together with neurons, endothelial cells may control nitric oxide-dependent vasodilation thereby regulating local blood flow in the brain.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009252	NADPH Dehydrogenase	A flavoprotein that reversibly oxidizes NADPH to NADP and a reduced acceptor. EC 1.6.99.1.	NADP Dehydrogenase,NADP Diaphorase,NADPH Diaphorase,Old Yellow Enzyme,TPN Diaphorase,Dehydrogenase, NADP,Dehydrogenase, NADPH,Diaphorase, NADP,Diaphorase, NADPH,Diaphorase, TPN,Enzyme, Old Yellow
D002560	Cerebrovascular Circulation	The circulation of blood through the BLOOD VESSELS of the BRAIN.	Brain Blood Flow,Regional Cerebral Blood Flow,Cerebral Blood Flow,Cerebral Circulation,Cerebral Perfusion Pressure,Circulation, Cerebrovascular,Blood Flow, Brain,Blood Flow, Cerebral,Brain Blood Flows,Cerebral Blood Flows,Cerebral Circulations,Cerebral Perfusion Pressures,Circulation, Cerebral,Flow, Brain Blood,Flow, Cerebral Blood,Perfusion Pressure, Cerebral,Pressure, Cerebral Perfusion
D004730	Endothelium, Vascular	Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.	Capillary Endothelium,Vascular Endothelium,Capillary Endotheliums,Endothelium, Capillary,Endotheliums, Capillary,Endotheliums, Vascular,Vascular Endotheliums
D006651	Histocytochemistry	Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.	Cytochemistry
D000594	Amino Acid Oxidoreductases	A class of enzymes that catalyze oxidation-reduction reactions of amino acids.	Acid Oxidoreductases, Amino,Oxidoreductases, Amino Acid
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
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
D014018	Tissue Distribution	Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.	Distribution, Tissue,Distributions, Tissue,Tissue Distributions