碩士 / 國立清華大學 / 生命科學系 / 90 / The effects of static magnetic field on the crayfish escape circuit were studied. The static magnetic field was found to increase the amplitude of excitatory postsynaptic potentials (EPSPs) and action potentials (APs). The effect of static magnetic field on EPSPs was similar with APs. The increasing effects will be present until the exposure time of static magnetic field was enough.
The reasons for the enhancement of EPSPs and APs may be that the concentration of Ca2+ in the nerve cell was modulated by the presence of static magnetic fields. The Ca2+ might be released from the intracellular Ca2+ stores (mitochondria or ER). The increasing concentration of Ca2+ could activate the protein kinase A and protein kinase C. These enzymes could activate another enzyme and finally change the activity of nerve cell to cause the enhancement of APs and EPSPs.
The input resistance and current were measured when the static magnetic fields was present. We found that the static magnetic field could increase the input resistance but not the current.
When the K+ channel blocker (TEA) occurred in crayfish buffer, the induction of potentiation was not occurred. So the static magnetic field may influence the nerve cells through the route like the TEA to influence the K+ channel on the cell membrane.
Because the above experiments were done in the isolated abdomens preparation, the inhibition descending from more rostral ganglia of the crayfish CNS to the abdomen didn’t occur in this kind of preparation. In the semi-intact preparations, the inhibition descending from more rostral ganglia of the crayfish CNS to the abdomen occurred, and the potentiation of EPSPs was inhibited. These results imply that static magnetic fields could not only induce the potentiation of EPSPs in the abdomen nerve cells but also activate the nerve cells in the CNS of crayfish.
| Identifer | oai:union.ndltd.org:TW/090NTHU0105079 |
| Date | January 2002 |
| Creators | Jenq-wei Yang, 楊正維 |
| Contributors | Shih-Rung Yeh, 葉世榮 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 40 |
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