Biomaterial Database

Ultracytochemical demonstration of monoamine oxidase activity in nervous and non-nervous tissue of the rat. 1977

J Müller, and C Da Lage

A method is described for the ultrastructural localization of the enzyme monoamine oxidase based on the formation of an osmiophilic formazan from the tetrazolium salt (2-(2'-benzothiazolyl)-5-styrl-3-(4'-phthalhydrazidyl) tetrazolium chloride) (BSPT) and using tryptamine as substrate. It was tested in rat heart, liver, adrenal cortex and medulla, kidney, pineal gland, cerebral cortex and cerebellar cortex and was found to provide good ultrastructural preservation, high contrast of the specific, enzyme-dependent precipitate and improved sensitivity. Monoamine oxidase activity was found in the mitochondrial outer compartment, nuclear envelope and endoplasmic reticulum in all organs studied; it was also seen occasionally in plasma membranes of liver and heart. Similar localizations were observed in interstitial cells and capillary endothelial cells. The enzyme-dependent nature of the observed precipitate was verified by control experiments consisting of incubation of overfixed tissue, omission of substrate from the incubation medium, and incubation in the presence of a specific, nonreversible inhibitor, pargyline. These studies confirm and extend the results of cell fractionation studies using liver, demonstrate the widespread distribution of monoamine oxidase in tissues, and suggest that monoamine oxidase plays important functional roles in extraneuronal cells.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008566	Membranes	Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.	Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D008995	Monoamine Oxidase	An enzyme that catalyzes the oxidative deamination of naturally occurring monoamines. It is a flavin-containing enzyme that is localized in mitochondrial membranes, whether in nerve terminals, the liver, or other organs. Monoamine oxidase is important in regulating the metabolic degradation of catecholamines and serotonin in neural or target tissues. Hepatic monoamine oxidase has a crucial defensive role in inactivating circulating monoamines or those, such as tyramine, that originate in the gut and are absorbed into the portal circulation. (From Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 8th ed, p415) EC 1.4.3.4.	Amine Oxidase (Flavin-Containing),MAO,MAO-A,MAO-B,Monoamine Oxidase A,Monoamine Oxidase B,Type A Monoamine Oxidase,Type B Monoamine Oxidase,Tyramine Oxidase,MAO A,MAO B,Oxidase, Monoamine,Oxidase, Tyramine
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D009417	Nerve Tissue	Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.	Nervous Tissue,Nerve Tissues,Nervous Tissues,Tissue, Nerve,Tissue, Nervous,Tissues, Nerve,Tissues, Nervous
D009685	Nuclear Envelope	The membrane system of the CELL NUCLEUS that surrounds the nucleoplasm. It consists of two concentric membranes separated by the perinuclear space. The structures of the envelope where it opens to the cytoplasm are called the nuclear pores (NUCLEAR PORE).	Nuclear Membrane,Envelope, Nuclear,Envelopes, Nuclear,Membrane, Nuclear,Membranes, Nuclear,Nuclear Envelopes,Nuclear Membranes