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Behavioural evidence that magnetic field effects in the land snail, Cepaea nemoralis , might not depend on magnetite or induced electric currents
Author(s) -
Prato Frank S.,
Kavaliers Martin,
Carson Jeffrey J. L.
Publication year - 1996
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/(sici)1521-186x(1996)17:2<123::aid-bem6>3.0.co;2-5
Subject(s) - land snail , magnetite , snail , environmental science , electric field , biology , ecology , physics , paleontology , quantum mechanics
Although extremely low frequency (ELF) magnetic fields (<300 Hz) appear to exert a variety of biological effects, the magnetic field sensing/transduction mechanism(s) remains to be established. Here, using the inhibitory effects of magnetic fields on endogenous opioid peptide‐mediated “analgaesic” response of the land snail. Cepaea nemoralis, we addressed the mechanism(s) of action of ELF magnetic fields. Indirect mechanisms involving both induced electric fields and direct magnetic field detection mechanisms (e.g., magnetite, parametric resonance) were evaluated. Snails were exposed to a static magnetic field (B DC =78±1 μT) and to a 60 Hz magnetic field (B AC =299±1 μT peak) with the angle between the static and 60 Hz magnetic fields varied in eight steps between 0° and 90°. At 0° and 90°, the magnetic field reduced opioid‐induced analgaesia by approximately 20%, and this inhibition was increased to a maximum of 50% when the angle was between 50° and 70°. Because B AC was fixed in amplitude, direction, and frequency, any induced electric currents would be constant independent of the B AC /B DC angle. Also, an energy transduction mechanism involving magnetite should show greatest sensitivity at 90°. Therefore, the energy transduction mechanism probably does not involve induced electric currents or magnetite. Rather, our results suggest a direct magnetic field detection mechanism consistent with the parametric resonance model proposed by Lednev. © 1996 Wiley‐Liss, Inc.