60 Hz electric field upregulates cytosolic Ca2+ level in mouse splenocytes stimulated by lectin

• Published in: Bioelectromagnetics Vol. 25; no. 3; pp. 204 - 210
• Main Authors: Harakawa, Shinji, Inoue, Noboru, Saito, Atsushi, Doge, Fuyuki, Nagasawa, Hideyuki, Suzuki, Naoyoshi, Martin, David E.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.04.2004
• Subjects: alternating current; Animals; concanavalin A; Concanavalin A - pharmacology; current density; Cytosol - drug effects; Cytosol - metabolism; Electricity; extremely low frequency; Female; Flow Cytometry; Mice; Mice, Inbred BALB C; phytohemagglutinin; Phytohemagglutinins - pharmacology; Spleen - cytology; Spleen - drug effects; Spleen - metabolism
• ISSN: 0197-8462; 1521-186X
• DOI: 10.1002/bem.10187

The effect of a 60 Hz electric field (EF) on alteration of cytosolic free Ca2+ level ([Ca2+]c) was examined in mouse splenocytes stimulated by lectins, namely concanavalin A (ConA) or phytohemagglutinin. In order to understand the role of EF on alterations in [Ca2+]c and to determine whether EF exposure increased cell mortality the splenocytes were cultured under the 60 Hz EFs producing current densities of 6 or 60 μA/cm2 for 30 min or 24 h. Cell mortality was less than 2% in experimental all conditions. [Ca2+]c in the splenocyte was not changed by the 6 μA/cm2 exposure alone, while a lectin‐induced [Ca2+]c elevation in the EF exposed cells was significantly higher than that of the sham exposed cells (P < .05: ANOVA, P < .05: paired t‐test). Moreover, the enhanced increase of [Ca2+]c in the EF exposed, lectin stimulated cells was only observed in the presence of extracellular Ca2+. The EF dependent upregulation of [Ca2+]c persisted after EF exposure (P < .05: paired t‐test). The results clearly indicate that Ca2+ influx across the plasma membrane is responsible for the enhanced increase of [Ca2+]c in the EF exposed, lectin stimulated cells and that EF has persistent effect on the cells. Although the precise mechanisms of the EF dependent upregulation of [Ca2+]c is not fully elucidated, the present results demonstrate that the 60 Hz EF (6 μA/cm2) affects [Ca2+]c during cell activation via a Ca2+ influx pathway induced by lectin stimulation. Bioelectromagnetics 25:204–210, 2004. © 2004 Wiley‐Liss, Inc.