[Effects of 50 Hz sinusoidal magnetic field on Ca2+ release channel ryanodine receptor of sarcoplasmic reticulum vesicles].

Abstract

OBJECTIVE: To investigate the effects of sinusoidal magnetic field on isolated sarcoplasmic reticulum (SR) calcium release channel (RyR1) function. METHODS: With the Ca2+ dynamic spectrum and isotope labeled methods, the Ca2+ release and [(3)H]-Ryanodine binding, the initial rates of NADH oxidation and the production of superoxide of SR exposed to 50 Hz sinusoidal magnetic field (MF) were investigated respectively. RESULTS: 0.4 mT, 50 Hz sinusoidal MF exposure for 30 min increased SR Ca2+ release initial rate about 35% from (10.82 +/- 0.89) pmol.mg(-1) pro.s(-1) to (14.69 +/- 1.21) pmol.mg(-1) pro.s(-1); and the [(3)H]-Ryanodine binding by about 15% from (2.13 +/- 0.05) pmol/mg pro to (2.45 +/- 0.07) pmol/mg pro, which regulated by 1 mmol/L NADH with 1 mmol/L NAD+. Meanwhile MF upregulated the rate of NADH oxidation by about 22% from (0.88 +/- 0.11) x 10(-4) FI/s to (1.07 +/- 0.13) x 10(-4) FI/s and upregulated the production of superoxide by about 32% from (0.99 +/- 0.09) x 10(-5) FI/s to (1.31 +/- 0.06) x 10(-5) FI/s. CONCLUSION: 0.4 mT sinusoidal MF increases the activity of RyR1 within the low redox potential environment, and promotes NADH oxidase activity and superoxide production.

AI evidence extraction

Main findings

Exposure of isolated sarcoplasmic reticulum vesicles to a 0.4 mT, 50 Hz sinusoidal magnetic field for 30 minutes increased the initial rate of SR Ca2+ release (~35%) and [(3)H]-ryanodine binding (~15%) under conditions regulated by 1 mmol/L NADH with 1 mmol/L NAD+. The magnetic field also increased the rate of NADH oxidation (~22%) and superoxide production (~32%).

Outcomes measured

• SR Ca2+ release initial rate
• [(3)H]-Ryanodine binding (RyR1)
• rate of NADH oxidation
• superoxide production

Limitations

• In vitro study using isolated sarcoplasmic reticulum vesicles; findings may not translate to whole organisms or humans
• Sample size and replication details not reported in the abstract
• Exposure conditions limited to a single field strength (0.4 mT) and duration (30 min)

Suggested hubs

• occupational-exposure (0.35)
  Published in an industrial hygiene/occupational diseases journal and involves 50 Hz magnetic field exposure relevant to workplace ELF environments.

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    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "other",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "30 min"
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "SR Ca2+ release initial rate",
        "[(3)H]-Ryanodine binding (RyR1)",
        "rate of NADH oxidation",
        "superoxide production"
    ],
    "main_findings": "Exposure of isolated sarcoplasmic reticulum vesicles to a 0.4 mT, 50 Hz sinusoidal magnetic field for 30 minutes increased the initial rate of SR Ca2+ release (~35%) and [(3)H]-ryanodine binding (~15%) under conditions regulated by 1 mmol/L NADH with 1 mmol/L NAD+. The magnetic field also increased the rate of NADH oxidation (~22%) and superoxide production (~32%).",
    "effect_direction": "harm",
    "limitations": [
        "In vitro study using isolated sarcoplasmic reticulum vesicles; findings may not translate to whole organisms or humans",
        "Sample size and replication details not reported in the abstract",
        "Exposure conditions limited to a single field strength (0.4 mT) and duration (30 min)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "50 Hz",
        "sinusoidal magnetic field",
        "0.4 mT",
        "ELF magnetic field",
        "sarcoplasmic reticulum",
        "ryanodine receptor",
        "RyR1",
        "calcium release",
        "NADH oxidation",
        "superoxide"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.34999999999999997779553950749686919152736663818359375,
            "reason": "Published in an industrial hygiene/occupational diseases journal and involves 50 Hz magnetic field exposure relevant to workplace ELF environments."
        }
    ]
}

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