Lateral gradients significantly enhance static magnetic field‐induced inhibition of pain responses in mice—a double blind experimental study

Abstract

Recent research demonstrated that exposure of mice to both inhomogeneous (3–477 mT) and homogeneous (145 mT) static magnetic fields (SMF) generated an analgesic effect toward visceral pain elicited by the intraperitoneal injection of 0.6% acetic acid. In the present work, we investigated behavioral responses such as writhing, entry avoidance, and site preference with the help of a specially designed cage that partially protruded into either the homogeneous (ho) or inhomogeneous (inh) SMF. Aversive effects, cognitive recognition of analgesia, and social behavior governed mice in their free locomotion between SMF and sham sides. The inhibition of pain response (I) for the 0–5, 6–20, and 21–30 min periods following the challenge was calculated by the formula I = 100 (1 − x/y) in %, where x and y represent the number of writhings in the SMF and sham sides, respectively. In accordance with previous measurements, an analgesic effect was induced in exposed mice (Iho = 64%, P < 0.0002 and Iinh = 62%, P < 0.002). No significant difference was found in the site preference (SMFho, inh vs. sham) indicating that SMF is neither aversive nor favorable. Comparison of writhings observed in the sham versus SMF side of the cage revealed that SMF exposure resulted in significantly fewer writhings than sham (Iho = 64%, P < 0.004 and Iinh = 81%, P < 0.03). Deeper statistical analysis clarified that the lateral SMF gradient between SMF and sham sides could be responsible for most of the analgesic effect (Iho = 91%, P < 0.02 and Iinh = 54%, P < 0.02). Bioelectromagnetics 34:385–396, 2013. © 2012 Wiley Periodicals, Inc.

Analgesic Effect of Textile Supports with Static Field Magnets in Patients with Osteoarticular Pain Syndrome: Results of a Randomized, Placebo Controlled, Double Blind Clinical Trial

“…Our results are in keeping with those reported in a very recent double blind experimental study in mice [8] in which pain was elicited by intraperitoneal injection of 0.6% acetic acid. In this study [8], the authors investigated behavioral responses (such as writhing) of mice to pain with the help of a specially designed cage that partially protruded into static magnetic fields. Cognitive recognition of analgesia was evaluated by comparing writhing of mice when they were on the side of cage exposed to static magnetic fields and when they were on the sham sides of the same cage.…”

Non‐thermal extremely low frequency magnetic field effects on opioid related behaviors: Snails to humans, mechanisms to therapy

“…This interpretation would be consistent with data summarized in Table associated with animal orientation. This is also consistent with reports that suggest it was not static magnetic field but its gradient that was more important for induction of analgesia [Kiss et al, ]. Also it has recently been shown that pigeons can detect changes in a static magnetic field inclination, which would correspond to an induced ELF if magnetic field detector was at a fixed inclination [Mora et al, ].…”

“…The paper by Betancur et al [] on effects of simultaneous light exposure used a non‐uniform static field. The extensive work of Laszlo reported effects of both homogenous and non‐homogenous magnetic fields [Laszlo et al, ; Sándor et al, ; Laszlo and Hernadi, ; Kiss et al, ; Hernadi and Laszlo ]. Of interest is data and speculation by this group that it is not the average amplitude of static magnetic field but its gradient that is responsible for inducing analgesia [Kiss et al, ].…”

“…The extensive work of Laszlo reported effects of both homogenous and non‐homogenous magnetic fields [Laszlo et al, ; Sándor et al, ; Laszlo and Hernadi, ; Kiss et al, ; Hernadi and Laszlo ]. Of interest is data and speculation by this group that it is not the average amplitude of static magnetic field but its gradient that is responsible for inducing analgesia [Kiss et al, ]. Nevertheless, in the same article, Kiss et al summarized their experimental data showing induction of analgesia as a function of static magnetic field strength with a saturation of effects at 200 mT.…”

Analysis of the Effect of Locally Applied Inhomogeneous Static Magnetic Field-Exposure on Mouse Ear Edema – A Double Blind Study

“…We monitored ear thickness 8 times during a 6 h time period post-challenge and set ourselves the following hypotheses: (i) continuous inhomogeneous SMF-exposure affects ear thickness of immobilized, MO-treated mice; consequently, if found true, the effect is exclusively due to magnetic interaction with the living tissues without induced electric phenomena, (ii) SMF application including whole-body exposure or local on the spine, on the head, or on the ear is similarly effective in MO-induced ear edema, (iii) local SMF-exposure on the spine or on the head can replace whole-body exposure in its effect on ear thickness in mice (if any). The magnetic induction values in the exposure conditions of the present work ranged between 2.8 mT and 476.7 mT proven to be optimized for small animal experiments [ 3 , 4 ].…”