RESUMO
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) Assuntos
Adenosina/metabolismo
, Astrócitos/citologia
, Astrócitos/metabolismo
, Córtex Cerebral/metabolismo
, Consumo de Oxigênio/fisiologia
, Oxigênio/metabolismo
, Nucleotídeos de Adenina/metabolismo
, Nucleotídeos de Adenina/fisiologia
, Adenosina/biossíntese
, Animais
, Astrócitos/efeitos dos fármacos
, Técnicas de Cultura de Células
, Células Cultivadas
, Córtex Cerebral/citologia
, Córtex Cerebral/patologia
, Líquido Extracelular/metabolismo
, Hipoxantina/metabolismo
, Hipóxia Encefálica/metabolismo
, Hipóxia Encefálica/patologia
, Inosina/metabolismo
, Ratos