Cross-talks between nucleotide receptor-inducedsignaling pathways in serumdeprived andnon-starved glioma C6 cells

摘要

Extracellular adenine and uridine nucleotides may influence cell metabolism bystimulation of specific receptors present on the surface of the plasma membrane.These compounds may directly interact with P2 nucleotide receptors or through ametabolite such as adenosine, interacting with A1–A3 receptors (Burnstock, 1978).The large family of P2 receptors is divided into two groups: P2X, the intrinsic ligand-gated ion channels, and P2Y, the members of G protein-coupled receptorsuperfamily (Abbracchio and Burnstock, 1994; Boeynaems et al., 2000). So far,P2X receptor subtypes have been subclassified as P2X1 to P2X7, whereas P2Yreceptors have been subclassified as P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13and P2Y14. It has been found that the P2Y, receptor responds selectively to ADP,while ATP may act as its partial antagonist. Moreover, 2-methylthio-ATP, 2-methylthio-ADP and 2-chloro-ATP are selective agonists of the P2Y1 receptor witha high potency, while UTP is not effective. In contrast, the P2Y2 receptor respondsto both ATP and UTP, while 2MeSATP has no effect. P2Y4 and P2Y6 receptors areselective for UTP and UDP, respectively, whereas the P2Y11 receptor is selective forATP but not for UTP (Boarder and Hourani, 1998; Czajkowski and Baranska, 2002;King et al., 1998).