Purinoceptor-mediated calcium signaling in primary neuron-glia trigeminal cultures

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• 作者：Stefania Ceruti ; Marta Fumagalli ; Giovanni Villa ; Claudia Verderio ; Maria P. Abbracchio
• 关键词：Calcium signaling ; P2 purinoceptors ; Satellite glial cells ; Bradykinin
• 刊名：Cell Calcium
• 出版年：2008
• 出版时间：June 2008
• 年：2008
• 卷：43
• 期：6
• 页码：576-590
• 全文大小：2105 K

文摘

Receptors for extracellular nucleotides (the P2X-calcium channels and the phospholipase C-coupled P2Y receptors) play key roles in pain signaling, but little is known on their function in trigeminal ganglia, whose hyperactivation leads to the development of migraine pain. Here we characterize calcium signaling via P2X₃ and P2Y receptors in primary mouse neuron-glia trigeminal cultures. Comparison with intact ganglion showed that, in dissociated cultures, sensory neurons retain, at least in part, their physical relationships with satellite glia. RT-PCR indicated expression of P2X₂/P2X₃ (confirmed by immunocytochemistry) and of all cloned P2Y receptors. Single-cell calcium imaging with subtype-selective P2-agonists/antagonists revealed presence of functional neuronal P2X₃, as well as of ADP-sensitive P2Y_1,12,13 and UTP-activated P2Y₂/P2Y₄ receptors on both neurons and glia. Calcium responses were much higher in glia, that also responded to UDP, suggesting functional P2Y₆ receptors. To study whether trigeminal ganglia P2 receptors are modulated upon treatment with pro-inflammatory agents, cultures were acutely (up to 3 min) or chronically (24 h) exposed to bradykinin. This resulted in potentiation of algogenic P2X₃ receptor-mediated calcium responses followed by their down-regulation at 24 h. At this exposure time, P2Y receptors responses in satellite glia were instead upregulated, suggesting a complex modulation of P2 receptors in pain signaling.