Nonthermal 60 Hz sinusoidal magnetic‐field exposure enhances ⁴⁵Ca²⁺ uptake in rat thymocytes: dependence on mitogen activation

Abstract

The effect of a 60 Hz sinusoidal magnetic field of nonthermal intensity on Ca2+ metabolism in rat thymic lymphocytes (thymocytes) was assessed in resting cells and in cells activated with the mitogen Concanavalin A (Con A). A 60 min exposure at 37°C to an induced electric field of 1.0 produced an average 2.7‐fold increase in Con A‐dependent 45Ca2+ ‐uptake compared to non‐exposed, isothermal control cells. In contrast, 45Ca2+ uptake remained unaltered during exposure of resting thymocytes. It was also found that thymocytes with a diminished ability to mobilize Ca2+ in response to Con A were most sensitive to the 60 Hz magnetic field. Although the precise mechanism of field interaction is at present unknown, modulation of Ca2+ metabolism during cell activation may represent a common pathway for field coupling to cellular systems.

Cellular target of weak magnetic fields: ionic conduction along actin filaments of microvilli

“…Other studies showed an increase of Ca 2ϩ influx in prestimulated rat thymocytes (86) and lymphocytes (52,53).…”

“…Experiments with different cell types consistently point to the Ca 2ϩ signaling system as the primary cellular target of MF interactions (5,10,23,52,53,60,69,86,87). In many cases, alternating MFs alone or in combination with static fields increase intracellular Ca 2ϩ , as, for instance, in HL60 cells (10), T-lymphocytes and leukemia cells (60), the human T cell line (Jurkat) (55,56), bone cells (23), pituitary cells (5), and human astrocytoma cells (69).…”

“…In some studies, MFs strongly amplify the Ca 2ϩ influx into cells with prestimulated Ca 2ϩ signal pathways (52,53,86). Under these conditions, Ca 2ϩ currents flowing through activated microvillar pathways may give rise to magnetic microfields around the ionic pathways of microvilli, which can interact with external MFs.…”

50-Hertz Magnetic Field and Calcium Transients in Jurkat Cells: Results of a Research and Public Information Dissemination (RAPID) Program Study

“…However, several investigations have not detected an effect of MF on calcium metabolism or flux in a variety of cell types (11)(12)(13)(14)(15). This (24) reported that calcium uptake in rat lymphocytes was increased by brief exposures to 60-Hz MF only in cells stimulated with the mitogen concanavalin A (ConA). In this study, those lymphocytes least responsive to ConA exhibited the greatest response to MF.…”

Use of Annexin V based Sperm Selection in Assisted Reproduction

“…Thus, the concentration and/or lifetime of free radicals that escape from the radical pair would increase by exposure to SMF, and free radicals initiate membrane lipids, proteins and DNA damage, and may lead to apoptosis or necrosis [89,90]. The diversity of alterations reported for SMF exposure may be related to varied duration, intensity, tissue penetration, and the type of cells [86,91]. In reproductive tissues, SMF has been shown to modulate the activity of several enzymes related to oxidative stress in the testicles of exposed rats [92].…”