Effect of Cytoskeletal Reagents on Stretch Activated Ion Channels.

摘要

Mechanically sensitive ion channels have been proposed to respond to membrane tension. We have developed methods to measure the membrane, tension in a patch and have examine the stress strain relationship. The results show that, in general, tension is the critical variable. However, we have also found one channel in glial cells whose gating is additionally dependent upon the curvature of the membrane. Stresses in a patch caused by suction lead to lipid flow along the wall of the pipette, but the flow is constrained by the highly extensible cytoskeleton whose area elastic constant is ca. 50dyn/cm. We developed tools to use high voltage electron microscopy to study the structure of patches and have characterized the placement of cytoskeleton, lipids and receptors in a variety of preparations. We also developed a new algorithm to align projections for tomography in order to examine the three dimensional structure of patches. We have demonstrated mechanically induced release of calcium via stretch activated ion channels in heart cells extending work on the molecular level to the whole cell level.... Mechanical transduction, Patch, Calcium, Electron microscopy, Light microscopy, Tomography.