ABSTRACT
Brain tissue oxygenation affects cerebral function and blood flow (CBF). Adenosine (Ado), a purine nucleoside, moderates neuronal activity, and arterial diameter. The cellular source of Ado in brain remains elusive; however, astrocytes are a logical site of production. Using astrocytic cultures, we tested the hypothesis that astrocytic derived Ado reflects cerebral oxygenation. We found that during alterations in pO(2), extracellular levels of Ado [Ado](e) changed rapidly. Graded reductions of oxygen tension revealed that[Ado](e) reached 10(-7) M to 10(-6) M with a pO(2) of 30-10mmHg, comparable with [Ado](e) and oxygen levels found in brain tissue during normoxemia. Higher O(2) levels were associated with a depression of [Ado](e). Under conditions of low pO(2) (pO(2) Subject(s)
Adenosine/metabolism
, Astrocytes/cytology
, Astrocytes/metabolism
, Cerebral Cortex/metabolism
, Oxygen Consumption/physiology
, Oxygen/metabolism
, Adenine Nucleotides/metabolism
, Adenine Nucleotides/physiology
, Adenosine/biosynthesis
, Animals
, Astrocytes/drug effects
, Cell Culture Techniques
, Cells, Cultured
, Cerebral Cortex/cytology
, Cerebral Cortex/pathology
, Extracellular Fluid/metabolism
, Hypoxanthine/metabolism
, Hypoxia, Brain/metabolism
, Hypoxia, Brain/pathology
, Inosine/metabolism
, Rats
