Ca2+ permeability of human heteromeric nAChRs expressed by transfection in human cells

P. Lax, S. Fucile, F. Eusebi

Research output: Contribution to journalArticle

Abstract

The Ca2+ permeability of the human heteromeric α3β4, α4β2 and α4β4 neuronal nicotinic acetylcholine receptors (nAChRs) was estimated by measuring the fractional Ca2+ current (Pf) flowing through the ligand-activated receptor-channels. Simultaneous recordings of transmembrane currents and fluorescence transients, using the whole-cell patch-clamp technique combined with fura-2 fluorescence microscopy, were performed in transiently transfected human cells. The human α4β2 nAChR showed a Pf value of 2.6%, while the human α3β4 nAChR showed a similar Pf value of 2.7%. Conversely, α4β4 nAChR exhibited a Pf value (1.5%) significantly smaller than those of both α4β2 and α3β4 nAChRs. In test experiments performed in HEK 293 cells stably expressing rat GluR1 AMPA receptor subunit, we repeated the determination of Pf, whose value (3.2%) has previously been reported by others using the same fluorescent dye; and we found a very similar Pf value (3.5%). In further test experiments, we found that Pf values of chick α3β4 (4.4%) and α4β4 (2.1 %) matched those previously reported by us using confocal fluorescence microscopy. Thus, our findings are consistent with those elsewhere reported even using different experimental procedures, giving a strong support to the following sequence of Ca2+ permeability: h-α3β4 > h-α4β2 > h-αAβ4.

Original languageEnglish
Pages (from-to)53-58
Number of pages6
JournalCell Calcium
Volume32
Issue number2
DOIs
Publication statusPublished - Aug 2002

Keywords

  • Ca permeability
  • Fractional Ca current
  • nAChRs

ASJC Scopus subject areas

  • Cell Biology
  • Endocrinology

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