Light-dependent and -independent behavioral effects of extremely low frequency magnetic fields in a land snail are consistent with a parametric resonance mechanism
- Univ. of Western Ontario, London, Ontario (Canada)
- Univ. of Waterloo, Ontario (Canada). School of Optometry
Exposure to extremely low frequency (ELF) magnetic fields has been shown to attenuate endogenous opioid peptide mediated antinociception or analgesia in the terrestrial pulmonate snail, Cepaea nemoralis. Here the authors examine the roles of light in determining this effect and address the mechanisms associated with mediating the effects of the ELF magnetic fields in both the presence and absence of light. Specifically, they consider whether the magnetic field effects involve an indirect induced electric current mechanism or a direct effect such as a parametric resonance mechanism (PRM). They exposed snails in both the presence and absence of light at three different frequencies (30, 60, and 120 Hz) with static field values (B{sub DC}) and ELF magnetic field amplitude (peak) and direction (B{sub AC}) set according to the predictions of the PRM for Ca{sup 2+}. Analgesia was induced in snails by injecting them with an enkephalinase inhibitor, which augments endogenous opioid (enkephalin) activity. They found that the magnetic field exposure reduced this opioid-induced analgesia significantly more if the exposure occurred in the presence rather than the absence of light. However, the percentage reduction in analgesia in both the presence and absence of light was not dependent on the ELF frequency. This finding suggests that in both the presence and the absence of light the effect of the ELF magnetic field was mediated by a direct magnetic field detection mechanism such as the PRM rather than an induced current mechanism.
- Sponsoring Organization:
- Medical Research Council (Canada); Natural Sciences and Engineering Research Council of Canada, Ottawa, ON (Canada)
- OSTI ID:
- 462576
- Journal Information:
- Bioelectromagnetics, Vol. 18, Issue 3; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
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