Bradykinin-evoked non-specific cationic current in neuroblastoma-glioma hybrid (NG108-15) cells and its down-regulation through differentiation

Naofumi Tokutomi, Yoshiko Tokutomi, Koji Fukunaga, Eishichi Miyamoto, Katsuhide Nishi

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Effects of bradykinin (BK) on the membrane conductance and level of cytoplasmic free Ca2+ in undifferentiated and differentiated neuroblastoma-glioma hybrid (NG108-15) cells were studied using the nystatin-perforated patch-clamp technique and fura-2 fluorometry. Under voltage clamp at -20 mV, undifferentiated cells responded to BK at > 10-9 M, producing a biphasic current composed of an apamin-sensitive Ca2+ -activated K+ outward current and non-specific cationic inward current. Both current components corresponding to a biphasic elevation of [Ca2+]i were completely prevented by an intracellular perfusion with EGTA (1 mM) under conventional whole cell recording condition. Undifferentiated cells revealed almost no voltage sensitive Ca2+ current. In NG108-15 cells differentiated with 8-Br-cyclic AMP (1 mM) or rolipram (1 mM), an inhibitor of type IV phosphodiesterase, BK concentration required for the non-specific cationic current with amplitude of > 100 pA was much greater than that of undifferentiated cells. This suggests that the differentiated cells decreased BK-sensitivity in induction of the non-specific cationic current. The non-specific cationic channel is suggested to play roles as a source of Ca2+ entry in undifferentiated NG108-15 cells.

Original languageEnglish
Pages (from-to)202-206
Number of pages5
JournalBrain research
Volume657
Issue number1-2
DOIs
Publication statusPublished - 1994 Sep 19
Externally publishedYes

Keywords

  • Cytoplasmic free Ca
  • Fura-2 fluorometry
  • Neuroblastoma-glioma hybrid (NG108-15) cell
  • Non-specific cationic current
  • Perforated patch clamp technique

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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