Ceruti Stefania, Fumagalli Marta, Villa Giovanni, Verderio Claudia, Abbracchio Maria P
Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, University of Milan, via Balzaretti 9, 20133 Milan, Italy.
Cell Calcium. 2008 Jun;43(6):576-90. doi: 10.1016/j.ceca.2007.10.003. Epub 2007 Nov 26.
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 P2X(3) 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 P2X(2)/P2X(3) (confirmed by immunocytochemistry) and of all cloned P2Y receptors. Single-cell calcium imaging with subtype-selective P2-agonists/antagonists revealed presence of functional neuronal P2X(3), as well as of ADP-sensitive P2Y(1,12,13) and UTP-activated P2Y(2)/P2Y(4) receptors on both neurons and glia. Calcium responses were much higher in glia, that also responded to UDP, suggesting functional P2Y(6) 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 P2X(3) 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.
细胞外核苷酸受体（P2X钙通道和与磷脂酶C偶联的P2Y受体）在疼痛信号传导中起关键作用，但对于它们在三叉神经节中的功能却知之甚少，而三叉神经节的过度激活会导致偏头痛疼痛的发生。在此，我们对原代小鼠三叉神经神经元-神经胶质细胞培养物中通过P2X(3)和P2Y受体介导的钙信号进行了表征。与完整神经节的比较表明，在解离培养物中，感觉神经元至少部分保留了它们与卫星神经胶质细胞的物理关系。逆转录聚合酶链反应表明P2X(2)/P2X(3)（免疫细胞化学证实）以及所有克隆的P2Y受体均有表达。使用亚型选择性P2激动剂/拮抗剂进行单细胞钙成像显示，功能性神经元P2X(3)以及对ADP敏感的P2Y(1,12,13)和UTP激活的P2Y(2)/P2Y(4)受体在神经元和神经胶质细胞上均有存在。神经胶质细胞中的钙反应要高得多，并且对UDP也有反应，提示存在功能性P2Y(6)受体。为了研究用促炎剂处理后三叉神经节P2受体是否受到调节，培养物被急性（长达3分钟）或慢性（24小时）暴露于缓激肽。这导致致痛性P2X(3)受体介导的钙反应增强，随后在24小时时下调。在这个暴露时间，卫星神经胶质细胞中P2Y受体的反应反而上调，提示在疼痛信号传导中P2受体存在复杂的调节。
