Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been reported recently that adenosine and ATP produce dose- and tone-dependent responses in the feline pulmonary vascular (PV) bed. The present study was undertaken to investigate the mechanisms mediating vasoconstrictor (VC) responses to adenosine and ATP in the intact-chest, spontaneously breathing cat under conditions of controlled blood flow and constant left atrial pressure. The order of potency of adenosine receptor agonists to produce VC in the PV bed was the selective adenosine A1 receptor agonist R-phenylisopropyladenosine greater than the mixed A1, A2 receptor agonist, adenosine greater than the selective adenosine A2 receptor agonist, 2-phenylaminoadenosine. The dose-related increase in lobar arterial pressure in response to adenosine was blocked by an adenosine (P1) receptor antagonist, BWA1433U, the cyclooxygenase inhibitor, meclofenamate, and the thromboxane A2 receptor antagonist, SQ29548. The order of potency of ATP analogs to produce VC in the PV bed was alpha,beta-methylene ATP (alpha,beta-meATP) much greater than beta,tau-methylene ATP greater than ATP. BWA1433U inhibited VC responses to ATP without affecting responses to its degradation-resistant analogs beta,tau-methylene ATP and alpha,beta-meATP. In the presence of BWA1433U and a continuous intralobar infusion of the selective 5'-nucleotidase inhibitor, alpha,beta-methyleneadenosine-5'-diphosphate, ATP VC responses are significantly enhanced compared to those after BWA1433U. alpha,beta-Methyleneadenosine-5'-diphosphate had no effect on the VC response to U44069 after BWA1433U. Meclofenamate significantly inhibited the vasoconstrictor responses to ATP but not to alpha,beta-meATP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adenosine and ATP produce vasoconstriction in the feline pulmonary vascular bed by different mechanisms. 183 63

The subcellular distribution of the adenosine A2a receptor in rat striatum has been investigated using specific binding of the A2a-selective ligand [3H]-CGS 21680. After subcellular fractionation, the distribution of [3H]-CGS 21680 binding was similar to that of the cholinergic nerve terminal marker acetylcholinesterase rather than the more general membrane marker 5'-nucleotidase, with 42% of binding associated with the synaptosomal sub-fraction and 19% with a light membrane fraction. Binding of [3H]-CGS 21680 was also found to co-purify with the cholinergic nerve terminal marker choline acetyltransferase during immunoaffinity purification of striatal cholinergic nerve terminals. These results demonstrate that some adenosine A2a receptors are present on cholinergic nerve terminals in rat striatum.
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PMID:The subcellular distribution of [3H]-CGS 21680 binding sites in the rat striatum: copurification with cholinergic nerve terminals. 836 37