Extremely low-frequency electromagnetic fields promote in vitro neurogenesis via upregulation of Cav1-channel activity

✍ Scribed by Roberto Piacentini; Cristian Ripoli; Daniele Mezzogori; Gian Battista Azzena; Claudio Grassi

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 415 KB
• Volume: 215
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.21293

✦ Synopsis

Abstract

We previously reported that exposure to extremely low‐frequency electromagnetic fields (ELFEFs) increases the expression and function of voltage‐gated Ca^2+^ channels and that Ca^2+^ influx through Ca~v~1 channels plays a key role in promoting the neuronal differentiation of neural stem/progenitor cells (NSCs). The present study was conducted to determine whether ELFEFs influence the neuronal differentiation of NSCs isolated from the brain cortices of newborn mice by modulating Ca~v~1‐channel function. In cultures of differentiating NSCs exposed to ELFEFs (1 mT, 50 Hz), the percentage of cells displaying immunoreactivity for neuronal markers (β‐III‐tubulin, MAP2) and for Ca~v~1.2 and Ca~v~1.3 channels was markedly increased. NSC‐differentiated neurons in ELFEF‐exposed cultures also exhibited significant increases in spontaneous firing, in the percentage of cells exhibiting Ca^2+^ transients in response to KCl stimulation, in the amplitude of these transients and of Ca^2+^ currents generated by the activation of Ca~v~1 channels. When the Ca~v~1‐channel blocker nifedipine (5 µM) was added to the culture medium, the neuronal yield of NSC differentiation dropped significantly, and ELFEF exposure no longer produced significant increases in β‐III‐tubulin‐ and MAP2‐immunoreactivity rates. In contrast, the effects of ELFEFs were preserved when NSCs were cultured in the presence of either glutamate receptor antagonists or Ca~v~2.1‐ and Ca~v~2.2‐channel blockers. ELFEF stimulation during the first 24 h of differentiation caused Ca~v~1‐dependent increases in the number of cells displaying CREB phosphorylation. Our data suggest that ELFEF exposure promotes neuronal differentiation of NSCs by upregulating Ca~v~1‐channel expression and function. J. Cell. Physiol. 215: 129–139, 2008. © 2007 Wiley‐Liss, Inc.