On the basis of previous experience with biological effects of electromagnetic fields a potential effect of homogeneous sinusoidal magnetic field (50 Hz, 10 mT) on energy state of rat skeletal muscle was investigated. Two different total body exposures to magnetic field were selected: (1) repeated 1 hour exposure, 2 times a week for 3 months, and (2) acute 1.5 hour exposure (and the appropriate control groups). Important energy metabolites (adenosine triphosphate--ATP, creatine phosphate, creatine, lactate, pyruvate and inorganic phosphate) were analysed by enzymatic and spectroscopic methods in musculus gracilis cranialis. On the basis of the concentration of important energy metabolites the apparent Gibbs free energy of ATP hydrolysis and creatine charge was calculated. Our results demonstrate no influence of this low frequency magnetic field on the level of important energy metabolites in rat skeletal muscle. The conclusion of this study is that neither repeated exposure nor the acute exposure of rats to the sinusoidal magnetic field of given parameters has any important influence on the energy state of the skeletal muscle.
Rats were experimentally exposed to the chemical factor, inorganic manganese (Mn), and the physical factor, simulated radiation of mobile phone to detect possible interactions, resulting in changes of brain Mn level or other changes. In acute test, significant increase in brain Mn level was observed in rats exposed to both factors as compared to Mn only. Within subchronic 3-months' test such interaction did not appear, but in vivo observation of exposed rats at the end of the test have demonstrated signficant behavioral changes as compared to unexposed rats.
Manganese retention was observed in brains and in several other tissues of female Wistar rats after the intratracheal instillation of an inorganic manganese compound: manganese dioxide. Two categories of rats, younger (180 to 200g) and older (330 to 350g), were divided into a control group, in which animals received vehicle only (0.5 mL physiological saline), and an experimental group, in which rats received a dose of 0.48 mg of Mn/kg body weight (in 0.5 mL saline), twice a week for 3 months, for a total dosage of 11.80 mg of Mn/kg body weight. At the end of the exposure period, manganese retention in selected rat organs, brain, liver, kidney, and lung, was analyzed using atomic absorption spectrophotometry. At the end of the 6-wk or 12-wk manganese dioxide exposure period, analysis of variance of the manganese retention results revealed significant differences between Mn-exposed and unexposed rats in brain, kidney, and lung tissues (p<0.01) for both experimental age categories. Moreover, at the end of the 12-wk exposure period, significant results (p<0.05) between younger and older rats were obtained for both brain and kidneys. In both types of tissue, the manganese retention in the younger group was higher than that in older animals.
Some implications of cooperative potential of metal ions and electromagnetic fields' radiation (EMF) in carcinogenic processes are discussed. It is known that these factors, chemical and physical individually have connections with processes of oxidative stress. Special attention was paid to possible manifestation within the brain. Therefore, the entry of a few potentially neurotoxic metals into the brain is discussed.
The aim of this study was to detect the effect of a magnetic field on manganese transport into rat brains. An experimental group of Female Wistar rats was given 0.48 mg Mn2+ per kg body weight intratracheally twice a week for 3 months and simultaneously exposed to a magnetic field: B = 10 mT, f = 50 Hz for 1 hr. Rats in one control group of rats received the same dose of manganese as the experimental group but were not exposed to the magnetic field. Rats in a second control group had neither exposure to manganese nor exposure to the magnetic field. After the last dose, all rats were sacrificed and their brains and other tissues were analyzed for manganese content. The results indicated that the magnetic field had a positive effect on increasing the manganese content in the brains of rats in the experimental group relative to those of the control groups. Visual evoked potentials (VEP) measured at the end of the exposure periods on randomly selected experimental and control rats showed a shortened but not statistically significant latency of the P1 peak of VEP in rats that had been exposed to both factors but not in control rats.
Impact of metal in vitro administration on rat tissue oxygen consumption is referred in the first part. Toxicological implications of in vivo metal administration to rats and the study of potential penetration of metal into the rat brain, which may eventually result in oxygen radical production are presented in second part.
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