Detection of inhomogeneities in membrane ohmic resistance in geometrically complex systems
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Detection of inhomogeneities in membrane ohmic resistance in geometrically complex systems. / Svirskis, G; Hounsgaard, J; Gutman, A.
In: Membrane & cell biology, Vol. 14, No. 3, 01.01.2000, p. 413-20.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Detection of inhomogeneities in membrane ohmic resistance in geometrically complex systems
AU - Svirskis, G
AU - Hounsgaard, J
AU - Gutman, A
PY - 2000/1/1
Y1 - 2000/1/1
N2 - DC field-evoked transients in arbitrarily shaped neurons and syncytia were analyzed theoretically. In systems with homogeneous passive membrane properties, the transients develop much faster than the membrane discharges. Conductance of the proximal membrane could be larger due to the injury imposed by sharp electrode impalement. In this case, the transients have an overshoot and an undershoot when the field is switched on and off. The overshoot and undershoot decay with the time constant of the response to current injection. If the conductance of the distal membrane is larger, the fast transients develop only partially and have slow tails which decay according to the time constant of the response to current injection. We recorded DC field-evoked potentials in motoneurons in turtle spinal cord slices by sharp electrodes and in the whole-cell mode. All three theoretically predicted types of responses were observed. The sharp electrodes were found not to impose a shunt in 60% of recorded cells. Detection of various membrane inhomogeneities in 1D-syncytium is discussed. We also suggest that it is possible to detect the inhomogeneities in intercellular resistance of the syncytium and intracellular resistance of a neuron when the membrane passive properties are homogeneous.
AB - DC field-evoked transients in arbitrarily shaped neurons and syncytia were analyzed theoretically. In systems with homogeneous passive membrane properties, the transients develop much faster than the membrane discharges. Conductance of the proximal membrane could be larger due to the injury imposed by sharp electrode impalement. In this case, the transients have an overshoot and an undershoot when the field is switched on and off. The overshoot and undershoot decay with the time constant of the response to current injection. If the conductance of the distal membrane is larger, the fast transients develop only partially and have slow tails which decay according to the time constant of the response to current injection. We recorded DC field-evoked potentials in motoneurons in turtle spinal cord slices by sharp electrodes and in the whole-cell mode. All three theoretically predicted types of responses were observed. The sharp electrodes were found not to impose a shunt in 60% of recorded cells. Detection of various membrane inhomogeneities in 1D-syncytium is discussed. We also suggest that it is possible to detect the inhomogeneities in intercellular resistance of the syncytium and intracellular resistance of a neuron when the membrane passive properties are homogeneous.
KW - Animals
KW - Cell Membrane
KW - Electric Conductivity
KW - Electric Impedance
KW - Electrodes
KW - Electrophysiology
KW - Models, Theoretical
KW - Neurons
KW - Turtles
M3 - Journal article
C2 - 11368501
VL - 14
SP - 413
EP - 420
JO - Membrane and Cell Biology
JF - Membrane and Cell Biology
SN - 1023-6597
IS - 3
ER -
ID: 33731390