title: Sustained depolarization-induced propagation of [Ca2+]i oscillations in cultured DRG neurons: the involvement of extracellular ATP and P2Y receptor activation.
abstract: Recently emerging evidence implicates a number of neuroactive substances and their receptors in mediating complex cell-to-cell communications in the ganglia. In the present study, we characterized the nonsynaptic chemical coupling mediated by extracellular ATP in dorsal root ganglia (DRG) neuron cultures by using the real time imaging of ATP, whole-cell patch clamping, in conjunction with confocal calcium imaging. Sustained depolarization by electrical stimulation evoked intracellular Ca2+ concentrations ([Ca2+]i) oscillations in individual DRG neurons, and subsequent ATP-dependent propagation [Ca2+]i oscillations to surrounding non-stimulated neighbors. [Ca2+]i oscillations were suppressed by inositol-1,4,5-trisphosphate (IP3) receptor antagonist 2-APB, but not ryanodine. The propagation of [Ca2+]i oscillations was prevented by the presence of the ATP-degrading enzyme, apyrase, and completely abolished by the blockase of G protein-coupled purinergic receptors-PLC-IP3 pathway with suramin, U73122 or 2-APB. In parallel, sustained depolarization elicited robust ATP release and diffusion from the stimulation site. Moreover, exogenous application of ATP to DRG cultures in large concentration elicits the [Ca2+]i oscillations in most neurons. Taken together, this data demonstrates that sustained membrane depolarization elicited ATP release, acting through a highly sensitive P2Y receptors/IP3-mediated signaling pathway to mediate the propagation of intercellular Ca2+ signaling, which suggest a novel signaling pathway for neuronal communication in DRG.
authors.affiliation: Department of Neurobiology, Tongji Medical School, Huazhong University of Science and Technology, HUST, 13 Hangkong Road, Wuhan 430030, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.forename: Xiao-hua
authors.initials: XH
authors.lastname: Lv
authors.forename: Shao-qun
authors.initials: SQ
authors.lastname: Zeng
authors.forename: Shun-lian
authors.initials: SL
authors.lastname: Tian
authors.forename: Man
authors.initials: M
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001081:Apyrase / Q000378:metabolism; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D002478:Cells, Cultured; D004963:Estrenes / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010507:Periodicity; D058919:Purinergic P2 Receptor Antagonists; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D015398:Signal Transduction; D013498:Suramin / Q000494:pharmacology
chemical_list: C538758:2-aminoethyl diphenylborinate; D001896:Boron Compounds; D004963:Estrenes; D053496:Inositol 1,4,5-Trisphosphate Receptors; D058919:Purinergic P2 Receptor Antagonists; D011760:Pyrrolidinones; D018048:Receptors, Purinergic P2; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D012433:Ryanodine; D013498:Suramin; D000255:Adenosine Triphosphate; D001081:Apyrase; D002118:Calcium