adenosine

1. A condensation product of adenine and d-ribose; a nucleoside found among the hydrolysis products of all nucleic acid s and of the various adenine nucleotides. A. accumulates in severe combined immunodeficiency disease. 2. A potent coronary vasodilator used in place of exercise for radionuclide myocardial perfusion studies. SYN: 9-β-d-ribofuranosyladenine.

- a. cyclic phosphate a. 3′,5′-cyclic monophosphate.

- a. deaminase an enzyme found in mammalian tissues, capable of catalyzing the deamination of a., forming inosine and ammonia. A deficiency of a. deaminase can lead to one form of severe combined immunodeficiency disease.

- a. diphosphate a. 5′-diphosphate.

- a. kinase enzyme catalyzing the transfer of a phosphate group from MgATP to a., forming MgADP and AMP. An important step in nucleoside salvage.

- a. monophosphate (AMP) specifically, a.-5′-monophosphate. See adenylic acid.

- a. nucleosidase an enzyme hydrolyzing a. to adenine and d-ribose.

- a. phosphate specifically, a. 3′- or 5′-phosphate. See adenylic acid.

- a. tetraphosphate a condensation product of a. with tetraphosphoric acid at the 5′ position.

- a. triphosphate SYN: a. 5′-triphosphate.

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aden·o·sine ə-'den-ə-.sēn, -sən n a nucleoside C₁₀H₁₃N₅O₄ that is a constituent of RNA yielding adenine and ribose on hydrolysis

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n.

a nucleoside that contains adenine and the sugar ribose and occurs in ATP. It is also used as an anti-arrhythmic drug to stop supraventricular tachycardia and restore a normal heart rhythm. As such, it needs to be injected quickly, which may fleetingly make the patient feel faint and develop chest pain. Trade name: Adenocor.

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aden·o·sine (ə-denґo-sēn) 1. a purine nucleoside, adenine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid (RNA) and its nucleotides play major roles in the reactions and regulation of metabolism. Symbol A. 2. [USP] a preparation of adenosine, which acts as a cardiac depressant of automaticity in the sinus node and conduction in the atrioventricular node and also as a vasodilator; used as an antiarrhythmic in the treatment of paroxysmal supraventricular tachycardia and as a diagnostic adjunct, in conjunction with myocardial perfusion imaging, to induce coronary artery vasodilation in patients unable to exercise adequately to undergo an exercise stress test; administered intravenously.