Exposure of postnatal rats to a static magnetic field of 0.14 T influences functional laterality of the hippocampal high-affinity choline uptake system in adulthood; in vitro test with magnetic nanoparticles
著者:
Kristofikova Z, Cermak M, Benesova O, Klaschka J, Zach P
The detailed summary of this article is not available in your language or incomplete. Would you like to see a complete translation of the summary?
Then please contact us →
研究目的（著者による）
The aims of the study are: (i) to evaluate possible defects in lateralization of hippocampal high-affinity choline uptake system of rats exposed to a static magnetic field at postnatal days 7 or 14, (ii) to compare the effects of the positive (parallel orientation with a vertical component of geomagnetic field) and the negative (antiparallel orientation) static magnetic field and finally, (iii) to attempt to evaluate possible changes of hemicholinium-3 sensitive choline carriers (are directly connected with a synthesis of acetylcholine) mediated via magnetic field exposures of hippocampal synaptosomes in vitro.
詳細情報
Hippocampal high-affinity choline uptake activity on synaptosomes in vitro correspond with the activity of septohippocampal cholinergic neurons in vivo.
影響評価項目
神経系への影響: hippocampal high-affinity choline uptake activity on synaptosomes
permanent magnet with 5 cm distance between the poles
ばく露装置の詳細
Six 7 or 14 day old rats from two litters were exposed at a time by making three animals share one box with a perforated cover and placing the box between the poles of the magnet.
Additional information
Twelve 7 or 14 day old rats were used in the experiments, 6 of them were used for exposure where as the remaining 6 were placed in an identical box placed behind the exposure equipment, hence serving as control. The direction of magnetic induction vector was vertical. Positive as well negative static magnetic fields was utilized for exposure which were obtained by orienting the magnetic fields either parallel or anti-parallel to the vertical component of the geomagnetic field for positive or negative fields, respectively. This was achieved by using the north pole of the permanent magnet up and south pole of the magnet down to obtain positive fields and visa versa to obtain negative fields.
Exposure and control procedures were analogous to E1 with the only exception that the 6 animals used for exposure were from one litter. Mixed synaptosomes isolated separately from the right or left hippocampi of six 7 day, four 14 day and two 12 week old male rats were resuspended in 0.32 M sucrose and exposed to a positive or negative static magnetic field at room temperature. Mixed synaptosomes isolated separately from the right or left hippocampi of six 14 day or four 12 week old animals were resuspended in 0.32 M sucrose or on a synaptosomal suspension containing dextran-coated superparamagnetic nano particles (0.444 mg/ml). A part of sysnaptosomes with nano particles was exposed to a positive or negative static magnetic field at room temperature.
神経系への影響: hippocampal high-affinity choline uptake activity on synaptosomes (high-affinity transport of [³H] choline and specific binding of [³H] hemicholinium-3)
The data demonstrate that a single in vivo exposure of 7- or 14-day-old rats to a static magnetic field (0.14 T for 60-120 min) evokes asymmetric alterations in the activity of choline carriers in adulthood. Namely, the negative field mediated a more marked decrease in the right hippocampus. The positive field was ineffective. Moreover, differences between the carriers from the right and the left hippocampi were revealed on synaptosomes pretreated with superparamagnetic nanoparticles and exposed for 30 min in vitro. The positive field enhanced more markedly the activity of carriers from the right hippocampus, the negative that from the left hippocampus. The data demonstrate functionally teratogenic risks of the alterations in the orientation of the strong static magnetic field for postnatal brain development. The results suggest functional specialization of both hippocampi in rats. Choline carriers could be involved as secondary receptors in magnetoreception through direct effects of geomagnetic field on intracellular magnetite crystals. Nanoparticles applied in vivo should be a useful tool to evaluate magnetoreception in future research.
