Deformation and flow of membrane into tethers extracted from neuronal growth cones.

摘要: Membrane tethers are extracted at constant velocity from neuronal growth cones using a force generated by laser tweezers trap. A thermodynamic analysis shows that as the tether is extended, energy stored in bending and adhesion energies cell body "nonlocal" bending. It postulated dissipated three viscous mechanisms including membrane flow, slip between two monolayers form bilayer, cytoskeleton. The predicts experiments show linear relation velocity. Calculations based on analytical results experimental measurements of radius approximately 0.2 micron zero 8 pN give modulus for 2.7 x 10(-19) N.m an extraordinarily small "apparent surface tension" cone 0.003 mN/m, where apparent tension sum far-field, in-plane adhesion. Treatments with cytochalasin B D, ethanol, nocodazole affect but not ATP depletion affects neither, whereas large concentrations DMSO both. Under conditions data presented to dominant mechanism comes occurs when flows over treatment cause dramatic drop effective viscosity. If it cytoskeleton film water, then this water has mean thickness only 10 A.