Amplification of depolarization-induced and ryanodine-sensitive cytosolic Ca2+ elevation by synthetic carbocyclic analogs of cyclic ADP-ribose and their antagonistic effects in NG108-15 neuronal cells

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金沢大学大学院医学系研究科

We synthesized analogs modified in the ribose unit (ribose linked to N1 of adenine) of cyclic ADP-ribose (cADPR), a Ca2+-mobilizing second messenger. The biological activities of these analogs were determined in NG108-15 neuroblastoma × glioma hybrid cells that were pre-loaded with fura-2 acetoxymethylester and subjected to whole-cell patch-clamp. Application of the hydrolysis-resistant cyclic ADP-carbocyclicribose (cADPcR) through patch pipettes potentiated elevation of the cytoplasmic free Ca2+ concentration ([Ca2+]i) at the depolarized membrane potential. The increase in [Ca2+]i evoked upon sustained membrane depolarization was significantly larger in cADPcR-infused cells than in non-infused cells and its degree was equivalent to or significantly greater than that induced by cADPR or β-NAD+. 8-chloro-cADPcR and two inosine congeners (cyclic IDP-carbocyclic-ribose and 8-bromo-cyclic IDP-carbocyclic-ribose) did not induce effects similar to those of cADPcR or cADPR. Instead, 8-chloro-cADPcR together with cADPR or cADPcR caused inhibition of the depolarization-induced [Ca2+]i increase as compared with either cADPR or cADPcR alone. These results demonstrated that our cADPR analogs have agonistic or antagonistic effects on the depolarization-induced [Ca2+]i increase and suggested the presence of functional reciprocal coupling between ryanodine receptors and voltage-activated Ca 2+ channels via cADPR in mammalian neuronal cells. © 2005 International Society for Neurochemistry.

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詳細情報 詳細情報について

  • CRID
    1050564285901540480
  • NII論文ID
    120000809381
  • NII書誌ID
    AA00703243
  • ISSN
    00223042
  • Web Site
    http://hdl.handle.net/2297/1839
  • 本文言語コード
    en
  • 資料種別
    journal article
  • データソース種別
    • IRDB
    • CiNii Articles

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