Bursting responses of Lymnea neurons to microwave radiation.

Abstract

Microelectrode and voltage-clamp techniques were modified to record spontaneous electrical activity and ionic currents of Lymnea stagnalis neurons during exposure to a 900-MHz field in a waveguide-based apparatus. The field was pulse-modulated at repetition rates ranging from 0.5 to 110 pps, or it was applied as a continuous wave (CW). When subjected to pulsed waves (PW), rapid, burst-like changes in the firing rate of neurons occurred at SARs of a few W/kg. If the burst-like irregularity was present in the firing rate under control conditions, irradiation enhanced its probability of occurrence. The effect was dependent on modulation, but not on modulation frequency, and it had a threshold SAR near 0.5 W/kg. CW radiation had no effect on the firing rate pattern at the same SAR. Mediator-induced, current activation of acetyl-choline, dopamine, serotonin, or gamma-aminobutyric-acid receptors of the neuronal soma was not altered during CW or PW exposures and, hence, could not have been responsible for the bursting effect.

AI evidence extraction

Main findings

During exposure to 900-MHz fields, pulsed waves produced rapid burst-like changes in neuronal firing rate at SARs of a few W/kg, with a reported threshold near 0.5 W/kg; the effect depended on modulation but not modulation frequency. Continuous-wave exposure at the same SAR had no effect on firing rate pattern. Mediator-induced receptor current activation (acetyl-choline, dopamine, serotonin, gamma-aminobutyric-acid) was not altered during CW or PW exposures.

Outcomes measured

• neuronal firing rate pattern
• burst-like changes in firing rate
• ionic currents
• mediator-induced receptor currents (acetyl-choline, dopamine, serotonin, gamma-aminobutyric-acid)

Limitations

• Sample size not reported in abstract
• Exposure duration not reported in abstract
• SAR values described qualitatively (e.g., 'a few W/kg') without exact levels for all conditions

Suggested hubs

• mechanisms-neurophysiology (0.78)
  Reports modulation-dependent changes in neuronal firing patterns under RF exposure using electrophysiology methods.

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    "study_type": "animal",
    "exposure": {
        "band": "RF",
        "source": null,
        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Lymnea stagnalis neurons",
    "sample_size": null,
    "outcomes": [
        "neuronal firing rate pattern",
        "burst-like changes in firing rate",
        "ionic currents",
        "mediator-induced receptor currents (acetyl-choline, dopamine, serotonin, gamma-aminobutyric-acid)"
    ],
    "main_findings": "During exposure to 900-MHz fields, pulsed waves produced rapid burst-like changes in neuronal firing rate at SARs of a few W/kg, with a reported threshold near 0.5 W/kg; the effect depended on modulation but not modulation frequency. Continuous-wave exposure at the same SAR had no effect on firing rate pattern. Mediator-induced receptor current activation (acetyl-choline, dopamine, serotonin, gamma-aminobutyric-acid) was not altered during CW or PW exposures.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure duration not reported in abstract",
        "SAR values described qualitatively (e.g., 'a few W/kg') without exact levels for all conditions"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "900 MHz",
        "microwave radiation",
        "pulse-modulated",
        "continuous wave",
        "SAR threshold",
        "Lymnea stagnalis",
        "neurons",
        "bursting",
        "voltage clamp",
        "microelectrode"
    ],
    "suggested_hubs": [
        {
            "slug": "mechanisms-neurophysiology",
            "weight": 0.7800000000000000266453525910037569701671600341796875,
            "reason": "Reports modulation-dependent changes in neuronal firing patterns under RF exposure using electrophysiology methods."
        }
    ]
}

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