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Specific diadenosine pentaphosphate receptor coupled to extracellular regulated kinases in cerebellar astrocytes

2002; Wiley; Volume: 83; Issue: 2 Linguagem: Inglês

10.1046/j.1471-4159.2002.01111.x

1471-4159

Ana I. Jiménez, Enrique Castro, Esmerilda G. Delicado, Marı́a Teresa Miras-Portugal,

Genetics and Neurodevelopmental Disorders

Abstract In this study, we show specific intracellular responses evoked by the stimulation of astrocytes with the P 1 , P 5 ‐di(adenosine‐5′)pentaphosphate, Ap 5 A. The stimulation of astrocytes with micromolar concentrations of the dinucleotide elicited rapid increases in intracellular calcium concentration ([Ca 2+ ] i ), showing an EC 50 value of 15.27 ± 0.61 µ m . Moreover, the stimulation of cells with nanomolar concentrations of Ap 5 A, unable to induce calcium responses, increased the phosphorylated forms of extracellular‐signal regulated kinase 1/2 (ERK) with an EC 50 value of 9.8 ± 2.4 n m . The maximal activation was observed at 100 n m Ap 5 A, which was similar to that produced by epidermal growth factor (EGF) under the same experimental conditions. The present data reported here indicate that Ap 5 A mediated these effects by interacting with a specific receptor, not yet identified, which was different from the P2Y 1 and P2Y 2 /P2Y 4 receptors present in all individual astrocytes.