Purinoceptor-mediated calcium signaling in primary neuron-glia trigeminal cultures.
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.
Ceruti
Stefania
S
Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, University of Milan, via Balzaretti 9, 20133 Milan, Italy.
Fumagalli
Marta
M
Villa
Giovanni
G
Verderio
Claudia
C
Abbracchio
Maria P
MP
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009619:Nociceptors / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010146:Pain / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D011983:Receptors, Purinergic / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D058477:Receptors, Purinergic P2X3; D058925:Receptors, Purinergic P2Y12; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D012668:Trigeminal Ganglion / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D018836:Inflammation Mediators; C546409:P2rx3 protein, mouse; C548577:P2ry12 protein, mouse; D012333:RNA, Messenger; D011983:Receptors, Purinergic; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D058925:Receptors, Purinergic P2Y12; C099845:purinoceptor P2Y6; D001920:Bradykinin; D002118:Calcium