Configuration‐dependent variability of the effect of an electric field on the plasma glucocorticoid level in immobilized mice

Abstract

We recently reported that an immobilization stress-induced increase in glucocorticoid (GC) level was suppressed in mice exposed to an electric field (EF) of 50 Hz in a kV/m-dependent manner. In this study, we investigated the reproducibility of the suppressive effect induced by EF exposure by varying the voltage and distance between the electrodes (0.5 kV/50 mm, 1 kV/100 mm, 2 kV/200 mm) and comparing the effects on the plasma GC level. In addition, the effect of mice being in contact with the lower electrode or not was compared at 1 kV/100 mm. Immobilization-induced GC levels were significantly decreased in mice exposed to an EF at 1 kV/100 mm for 60 min (P < 0.01), but not in mice exposed to 0.5 kV/50 mm or 2 kV/200 mm. Furthermore, the suppressive effect of the 1 kV/100 mm EF was canceled when a polypropylene sheet (0.1 mm thick) was placed between the animal and lower electrode. Our findings corroborated that an EF of 10 kV/m inhibits stress-induced changes in the endocrine system in mice and demonstrated that this effect depends on the configuration of the EF exposure system, even when the EF strength remains the same. Bioelectromagnetics. 38:265-271, 2017. © 2017 Wiley Periodicals, Inc.

Characterization of the suppressive effects of extremely‐low‐frequency electric fields on a stress‐induced increase in the plasma glucocorticoid level in mice

“…6) is consistent with our previous findings that exposure to a 50-Hz EF at 17.5 kV/m suppressed increases in immobilization-induced stress hormones in rats [Harakawa et al, 2004] and that a 50-Hz EF at 10 kV/m suppressed the immobilization-induced GC increase in mice, at a relatively early phase during the immobilization-induced stress response Hori et al, 2017]. 6) is consistent with our previous findings that exposure to a 50-Hz EF at 17.5 kV/m suppressed increases in immobilization-induced stress hormones in rats [Harakawa et al, 2004] and that a 50-Hz EF at 10 kV/m suppressed the immobilization-induced GC increase in mice, at a relatively early phase during the immobilization-induced stress response Hori et al, 2017].…”

“…1) consisted of three major components: a high-voltage transformer unit (maximum output voltage, 30 kV; Hakuju, Tokyo, Japan), a constant-voltage unit (CVFT1-200H; Tokyo Seiden, Tokyo, Japan) to prevent unexpected interference from electrical noise originating from the commercial power supply, and a parallel plate electrode system [Harakawa et al, 2004;Hori et al, 2017]. 1) consisted of three major components: a high-voltage transformer unit (maximum output voltage, 30 kV; Hakuju, Tokyo, Japan), a constant-voltage unit (CVFT1-200H; Tokyo Seiden, Tokyo, Japan) to prevent unexpected interference from electrical noise originating from the commercial power supply, and a parallel plate electrode system [Harakawa et al, 2004;Hori et al, 2017].…”

“…2B) [Harakawa et al, 2004Hori et al, 2015Hori et al, , 2017. 2B) [Harakawa et al, 2004Hori et al, 2015Hori et al, , 2017.…”

“…We previously established an experimental system to evaluate the efficacy of power line-frequency, at least at 50 Hz, EF in the stress response induced by immobilization in rodents [Harakawa et al, 2004[Harakawa et al, , 2005Hori et al, 2015Hori et al, , 2017. We previously established an experimental system to evaluate the efficacy of power line-frequency, at least at 50 Hz, EF in the stress response induced by immobilization in rodents [Harakawa et al, 2004[Harakawa et al, , 2005Hori et al, 2015Hori et al, , 2017.…”

“…Elucidating the precise biological effects of power line-frequency EFs requires experimental methods for quantitative and qualitative assessment. We previously established an experimental system to evaluate the efficacy of power line-frequency, at least at 50 Hz, EF in the stress response induced by immobilization in rodents [Harakawa et al, 2004[Harakawa et al, , 2005Hori et al, 2015Hori et al, , 2017. With the experimental system, we have attempted to further the understanding of the effects of ELF EF exposure.…”