Ependymal cells along the lateral ventricle express functional P2X7 receptors

Ependymal cells line the cerebral ventricles and are located in an ideal position to detect central nervous system injury and inflammation. The signaling mechanisms of ependymal cells, however, are poorly understood. As extracellular adenosine 5'-triphosphate is elevated in the context of cellular damage, experiments were conducted to determine whether ependymal cells along the mouse subventricular zone (SVZ) express functional purinergic receptors. Using whole-cell patch clamp recording, widespread expression of P2X(7) receptors was detected on ependymal cells based on their antagonist sensitivity profile and absence of response in P2X(7) (-/-) mice. Immunocytochemistry confirmed the expression of P2X(7) receptors, and electron microscopy demonstrated that P2X(7) receptors are expressed on both cilia and microvilli. Ca2+ imaging showed that P2X(7) receptors expressed on cilia are indeed functional. As ependymal cells are believed to function as partner cells in the SVZ neurogenic niche, P2X(7) receptors may play a role in neural progenitor response to injury and inflammation.