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Possible mechanisms by which extremely low frequency magnetic fields affect opioid function
Author(s) -
Prato Frank S.,
Carson Jeffrey J. L.,
Ossenkopp KlausPeter,
Kavaliers Martin
Publication year - 1995
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.9.9.7601344
Subject(s) - amplitude , magnetic field , extremely low frequency , physics , nuclear magnetic resonance , stimulus (psychology) , inhibitory postsynaptic potential , condensed matter physics , neuroscience , biology , optics , psychology , quantum mechanics , psychotherapist
Although extremely low frequency (ELF, <300 Hz) magnetic fields exert a variety of biological effects, the magnetic field sensing/transduction mechanism (or mechanisms) remain to be identified. Using the well‐defined inhibitory effects that magnetic fields have on opioid peptide mediated antinocicep‐tion or “analgesia” in the land snail Cepaea nemoralis, we show that these actions only occur for certain frequency and amplitude combinations of time‐varying sinusoidal magnetic fields in a manner consistent with a direct influence of these fields. We exposed snails with augmented opioid activity to ELF magnetic fields, which were varied in both amplitude and frequency, along with a parallel static magnetic field. When the peak amplitude (0‐547 μT) of a magnetic field of 60 Hz was varied systematically, we observed a nonlinear response, i.e., a nonlinear reduction in analgesia as measured by the latency of a defined response by the snails to a thermal stimulus. When frequency (10‐240 Hz) was varied, keeping the amplitude constant (141 μT), we saw significant inhibitory effects between 30 and 35 Hz, 60 and 90 Hz and at 120 and 240 Hz. Finally, when the static field was varied but the amplitude and frequency of the time‐varying field were held constant, we observed significant inhibition at almost all amplitudes. This amplitude/frequency “resonance‐like” dependence of the magnetic field effects suggests that the mechanism (or mechanisms) of response to weak ELF fields likely involves a direct magnetic field detection mechanism rather than an induced current phenomenon. We examined the implications of our findings for several models proposed for the direct sensing of ELF magnetic fields.—Prato, F. S., Carson, J. J. L., Ossenkopp, K.‐P., Kavaliers, M. Possible mechanisms by which extremely low frequency magnetic fields affect opioid function. FASEB J. 9, 807‐814 (1995)