Inhibition of low- and high-threshold Ca2+ channels of human neuroblastoma IMR32 cells by Lambert-Eaton myasthenic syndrome (LEMS) IgGs

C. Grassi, V. Magnelli, V. Carabelli, E. Sher, E. Carbone

Research output: Contribution to journalArticlepeer-review

Abstract

IgGs from two LEMS patients applied to human neuroblastoma IMR32 cells reduced the density of low- (LVA; T) and high-threshold (HVA; L and N) Ba2+ currents by different percentages: 36% (LVA) and 56% (HVA) for one and 48% and 45% for the other. A pharmacological assay of IgGs action based on the block of L-type channel by nifedipine and on the delayed activation of N-type channel by noradrenaline, indicated a preferential inhibition of the N-type current in IMR32 cells (55% and 47% for the two patients). The L-type current, contributing to approximately one-third of the total, was also depressed by LEMS IgGs but to a minor degree (49% and 30%). Except for an increase of single N-type channel inactivation, LEMS antibodies preserved the elementary properties of single HVA channels, suggesting that the macroscopic current reduction after IgGs treatment is likely due to a decrease in the number of active HVA Ca2+ channels.

Original languageEnglish
Pages (from-to)50-56
Number of pages7
JournalNeuroscience Letters
Volume181
Issue number1-2
DOIs
Publication statusPublished - Nov 7 1994

Keywords

  • Ca channels
  • Human neuroblastoma
  • IgG
  • Lambert-Eaton syndrome

ASJC Scopus subject areas

  • Neuroscience(all)

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