NG-nitroarginine methyl ester (L-NAME) was used to exert an anti-depressive effect. It was diluted in physiological saline and administered intraperitoneally (30 mg/kg) after exposure.
72 male mice were divided into the following groups (n=9 each): 1) acute exposure, 2) chronic exposure, 3) acute exposure and administration of L-NAME, 4) acute exposure and administration of saline (sham administration). For each group, a separate sham exposure group was used.
Exposure duration: continuous for 2 hours
Exposure duration: continuous for 2 hours/day for 2 weeks (6 days/week, 1 day break)
|Setup||two pairs of coaxially arranged Helmholtz coils with winding embedded in a plexiglass frame; the diameter of each coil was 91.4 cm; the distance between the coils in the pairs was 50 cm and there were 60 turns of 2.5 mm copper wire oriented along the vector of the geomagnetic field; the centrally horizontal MF was homogenous in the plexiglass cage with 4-5 animals (groups were divided); the temperature during exposure did not exceed 27 °C|
|Sham exposure||A sham exposure was conducted.|
Chronic exposure (group 2) significantly reduced depressive-like behaviour compared to the sham exposure, while acute exposure (group 1) did not show significant differences compared to the sham exposure.
However, acute exposure in combination with L-NAME (group 3) significantly increased the depressive-like behaviour compared to the respective sham exposure and thus negating the anti-depressing effect of L-NAME.
Locomotor activity did no show any significant differences between the groups.
The authors conclude that chronic exposure of mice to a 50 Hz magnetic field could alter depressive-like behavior in mice. The reversion of the anti-depressive effect of L-NAME indicates a possible increase of nitric oxide in the brain due to the magnetic field exposure.