1992 Fiscal Year Final Research Report Summary
Biophysical and Molecularbiological Study on Stretch Channel
| Project/Area Number |
03044073
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
SOKABE Masahiro Nagoya University School of Medicine, 医学部, 教授 (10093428)
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| Co-Investigator(Kenkyū-buntansha) |
FREDERICK SA ニューヨーク州立大学, 医学部, 教授
SACHS Frederick State University of New York, Medical School
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| Project Period (FY) |
1991 – 1992
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| Keywords | SA-channel / Mechanical stimulation / Pach-clamping / Patch-membrane / Membrane-tension / Cytoskeleton |
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| Research Abstract |
The aim of this research project is to establish a method for the analysis of the stimulusresponse relationship in the stretch activated (SA) ion channel and to obtain a clue to isolate SA channel inolecules. The obtained results are follows.
(1) We have developed a theory to analyze transient response of the patch area to a stretch pulse, by which we could determine the mechanical property, like elasticity or viscocity, of the patch.
(2) Through the analysis by using above theoty, we found that most patch membranes with gigaseal have considerable amount of resting tension (ca. 5dyn/cm), that might generate during seal formation. This result is very important, because it can resolve the contradiction between microscopic (single channel) and macroscopic (whole cell) observations, where the macroscopic stretch activated responses are very hard to induce (Morris & Horn, 1991).
(3) We have developed a method to apply controllable stretches to the whole cell by growing cells on elastic thin silicon membranes. In addition we could successfully estimate whole cell SA channel activity through the measurement of intracellular Ca^<2+> increases by using Ca-microscopy.
(4) Taking the resting tension in the patch, the tension to activate SA channels in the patch was found to be comparable to that in intact cell membranes, which was measured by the method described in (3). This result strongly support the idea that the single SA channel activity observed by the patch clamping is involved in macroscopic stretchdependent cell responses.
(5) We have found potent blockers and activatiors for the SA channel. Some of them should be useful for the future study to identify and isolate SA channel molecules.
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