Medical/biological study (experimental study)

Extremely low frequency magnetic field induces hyperalgesia in mice modulated by nitric oxide synthesis med./bio.

By: Jeong JH, Kum C, Choi HJ, Park ES, Sohn UD

Published in: Life Sci 2006; 78 (13): 1407-1412

Aim of study (acc. to author)

To study the effect of extremely low frequency magnetic field on hyperalgesia in mice.

Background/further details

The possible nitric oxide (NO) system associated with the hyperalgesic effects of the exposure of extremely low frequency magnetic fields was considered. The involvement of calcium-dependent NO pathway in hyperalgesia was evaluated by blocking Ca²⁺ sources with NMDA receptor antagonist (MK-801) and calcium channel blocker (nimodipine).

Endpoint

effects on the neurological system: hyperalgesia; pain threshold

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 48 h	magnetic flux density: 2 mT effective value

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	unspecified
Exposure duration	continuous for 48 h

Exposure setup

Exposure source	Helmholtz coils
Setup	coils produced a magnetic field in the vertical direction at the center of the system with the cage located between the coil pair. Sham exposed mice were placed in the same location with the coils switched off.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2 mT	effective value	unspecified	-	-

Exposed system:

animal
mouse/ICR
whole body

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: nitric oxide level (UV spectrophotometry) and expression of calcium-dependent/independent constitutive/inducible nitric oxide synthase (Western blot) (to investigate NO mediated pain mechanism)
effects on the neurological system: hyperalgesia/pain threshold (hot plate test; latency (time elapsed until mice lick the feet, jump or rapidly stamp the feet))

Investigated system:

isolated bio./chem. substance
tissue homogenates (supernatants)
investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The exposure of animals to extremely low frequency magnetic field lowered pain threshold and elevated NO synthesis in brain and spinal cord.The hyperalgesic effects of extremely low frequency magnetic field were shown to be associated with calcium-dependent nitric oxide synthase.The expression of calcium-dependent constitutive nitric oxide synthases and calcium-independent inducibel nitric oxide synthases were not changed by extremely low frequency magnetic fields.
The authors suggest that extremely low frequency magnetic field produce hyperalgesia by modulating NO synthesis via Ca²⁺-dependent nitric oxide synthase.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Patruno A et al. (2015): mTOR Activation by PI3K/Akt and ERK Signaling in Short ELF-EMF Exposed Human Keratinocytes
Kumar S et al. (2013): Exposure to extremely low-frequency magnetic field restores spinal cord injury-induced tonic pain and its related neurotransmitter concentration in the brain
Cho SI et al. (2012): Extremely low-frequency magnetic fields modulate nitric oxide signaling in rat brain
Kosar MI et al. (2012): Antinociceptive Effects in Normal and Diabetic Rats Exposed to 50 Hz Magnetic Field
Rakesh RM et al. (2008): Threshold of pain in chronic magnetic field- (50 Hz, 17.9 microT) exposed rats: effect of sucrose ingestion
Manikonda PK et al. (2007): Influence of extremely low frequency magnetic fields on Ca2+ signaling and NMDA receptor functions in rat hippocampus
Reale M et al. (2006): Modulation of MCP-1 and iNOS by 50-Hz sinusoidal electromagnetic field