1988 Fiscal Year Final Research Report Summary
Research on the molicular mechanism of nervous excitation with the use of optical methods
| Project/Area Number |
61570056
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
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| Project Period (FY) |
1986 – 1987
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| Keywords | Nerve fiber / Optical activity / Excitability / Membrane / 光学シグナル |
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| Research Abstract |
Macromolecules in the axonal membrane are supposed to undergo structural changes when the nerve is excited. In order to detect such changes of membrane macromolecules, changes in optical properties, especially optical activity, of nerve fibers were examined when nerve was excited, The apparatus employed was a high speed polarimeter assembled in this laboratory. Calibration using sucrose solutions indicates that the apparatus was working adequately as a polarimeter. When nerve from walking legs of spiny lobsters was used as the experimental material, stimulation produced a change in optical rotation with maximum amplitude of about 500 degree. The time course was either monophasic or polyphasic, and the sign of the signal was also variable according to the preparation. It was possible to exclude contributions from electrical artefacts, scattering change, circular dichroism change and linear dichroism change. However,since birefringence change of nerve is large, a contribution from the bi
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refringence singal was often superimposed on the later phase of the optical rotation signal. The birefringence signal depends on the azimuth of the nerve whereas the optical rotation signal does not depend on the azinuth of the nerve. The distinction between the two signals could therefore be made by turning the nerve and changing its azimuth. Factors which determine the sign of the optical rotation signal was examined. The sign was independent of wavelength of light between 450-650 nm. It was also independent of side of walking legs from which nerve was taken. It depended however on the tension of the nerve during optical experiment. Stretching of the nerve sometimes caused reversal of the signal. Another factor which influenced the sign of the response was the direction of impulse conduction. When the optical signal was recorded at around the middle part of the nerve, the sign of the optical rotation signal depended on the side of stimulation. The phenomenon was observed about 80% of the examined preparation. the molecular mechanisms underlying these optical phenomena were discussed. Less
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Research Products
(10 results)
