We attached individual nerve cells from leech ganglia to oxidized silicon using poly-lysine. We studied the electrical current through the cell membrane in the region of adhesion taking advantage of field-effect transistors integrated in the substrate. We found that a minute mechanical deformation of the cell triggered a bistable reversible switching of the attached membrane between states of high and low conductance. Feasible mechanisms of the nonlinear effect are discussed.
Fig. 3: Reversible switching of the cell membrane revealed by
different relations of the intracellular voltage VM(t) (upper diagram)
and the extracellular voltage VJ(t) (black curve in lower
diagram). The microelectrode is lowered and lifted alternating.
(The intracellular voltage is superposed by a voltage
drop in the electrode during current injection for 10ms.)
Simulations of the extracellular voltage VJ(t) are shown as
red curve in the lower diagram using the record of the microelectrode as
a stimulus.
The resistances of membrane and seal are
RJM=300MW, RJ=2MW with the microelectrode lifted
and RJM=40MW, RJ=3.5MW with the microelectrode lowered.
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