A role for the magnetic field in the radiation-induced efflux of calcium ions from brain tissue in vitro

Abstract

Two independent laboratories have demonstrated that electromagnetic radiation at specific frequencies can cause a change in the efflux of calcium ions from brain tissue in vitro. In a local geomagnetic field (LGF) at a density of 38 microTesla (microT), 15- and 45-Hz electromagnetic signals (40 Vp-p/m in air) have been shown to induce a change in the efflux of calcium ions from the exposed tissues, whereas 1- and 30-Hz signals do not. We now show that the effective 15-Hz signal can be rendered ineffective when the LGF is reduced to 19 microT with Helmholtz coils. In addition, the ineffective 30-Hz signal becomes effective when the LGF is changed to +/- 25.3 microT or to +/- 76 microT. These results demonstrate that the net intensity of the LGF is an important variable. The results appear to describe a resonance-like relationship in which the frequency of the electromagnetic field that can induce a change in efflux is proportional to a product of LGF density and an index, 2n + 1, where n = 0,1. These phenomenological findings may provide a basis for evaluating the apparent lack of reproducibility of biological effects caused by low-intensity extremely-low-frequency (ELF) electromagnetic signals. In future investigations of this phenomenon, the LGF vector should be explicitly described. If the underlying mechanism involves a general property of tissue, then research conducted in the ambient electromagnetic environment (50/60 Hz) may be subjected to unnoticed and uncontrolled influences, depending on the density of the LGF.

AI evidence extraction

Main findings

In a local geomagnetic field (LGF) of 38 microT, 15- and 45-Hz electromagnetic signals (40 Vp-p/m in air) were reported to induce a change in calcium ion efflux from brain tissue in vitro, while 1- and 30-Hz signals did not. Reducing the LGF to 19 microT rendered the 15-Hz signal ineffective, and changing the LGF to +/-25.3 microT or +/-76 microT made the previously ineffective 30-Hz signal effective, suggesting LGF intensity modifies the frequency-dependent effect.

Outcomes measured

• Efflux of calcium ions from brain tissue

Limitations

• Sample size not reported in abstract
• Exposure duration not reported in abstract
• Outcome described as a change in efflux without direction/magnitude details in abstract
• In vitro findings; generalizability to in vivo/humans not addressed in abstract

Suggested hubs

• occupational-exposure (0.2)
  Mentions ambient 50/60 Hz environment as a potential uncontrolled influence, though study is in vitro and not explicitly occupational.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "other",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Brain tissue (in vitro)",
    "sample_size": null,
    "outcomes": [
        "Efflux of calcium ions from brain tissue"
    ],
    "main_findings": "In a local geomagnetic field (LGF) of 38 microT, 15- and 45-Hz electromagnetic signals (40 Vp-p/m in air) were reported to induce a change in calcium ion efflux from brain tissue in vitro, while 1- and 30-Hz signals did not. Reducing the LGF to 19 microT rendered the 15-Hz signal ineffective, and changing the LGF to +/-25.3 microT or +/-76 microT made the previously ineffective 30-Hz signal effective, suggesting LGF intensity modifies the frequency-dependent effect.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure duration not reported in abstract",
        "Outcome described as a change in efflux without direction/magnitude details in abstract",
        "In vitro findings; generalizability to in vivo/humans not addressed in abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "extremely-low-frequency",
        "ELF",
        "geomagnetic field",
        "local geomagnetic field",
        "Helmholtz coils",
        "calcium efflux",
        "brain tissue",
        "frequency-specific effects",
        "resonance-like relationship"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Mentions ambient 50/60 Hz environment as a potential uncontrolled influence, though study is in vitro and not explicitly occupational."
        }
    ]
}

Comments

Log in to comment.

No comments yet.