L‐[3H]Adenosine, a New Metabolically Stable Enantiomeric Probe for Adenosine Transport Systems in Rat Brain Synaptoneurosomes

J. G. Gu, S. Delaney, A. N. Sawka, J. D. Geiger

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Abstract: The stereoenantiomers D‐[3H]adenosine and L‐[3H]adenosine were used to study adenosine accumulation in rat cerebral cortical synaptoneurosomes. L‐Adenosine very weakly inhibited rat brain adenosine deaminase (ADA) activity with a Ki value of 385 μM. It did not inhibit rat brain adenosine kinase (AK) activity, nor was it utilized as a substrate for either ADA or AK. The rate constants (fmol/mg of protein/s) for L‐[3H]adenosine accumulation measured in assays where transport was stopped either with inhibitor‐stop centrifugation or with rapid filtration methods were 82 ± 14 and 75 ± 10, respectively. Using the filtration method, the rates of L‐[3H]adenosine accumulation were not significantly different from the value of 105 ± 15 fmol/mg of protein/s measured for D‐[3H]adenosine transport. Unlabeled D‐adenosine and nitrobenzylthioinosine, both at a concentration of 100 μM, reduced the levels and rates of L‐[3H]adenosine accumulation by >44%. These findings suggest that L‐adenosine, a metabolically stable enantiomeric analog, and the naturally occurring D‐adenosine are both taken up by rat brain synaptoneurosomes by similar processes, and as such L‐adenosine may represent an important new probe with which adenosine uptake may be studied.

Original languageEnglish (US)
Pages (from-to)548-552
Number of pages5
JournalJournal of Neurochemistry
Volume56
Issue number2
DOIs
StatePublished - Feb 1991
Externally publishedYes

Keywords

  • Adenosine
  • Adenosine deaminase
  • Adenosine kinase
  • Stereoselectivity
  • Synaptoneurosomes
  • Transport

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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