Question

1. A cell membrane with a total conductance of 45 nS is injected with a current of 4 nA. The length constant of the membrane is 2.0 mm. The magnitude of the depolarizationmeasured 2.5 mm from the point of injection and recorded 1.0 ms after the beginning of the injection is 1.5 mV. Knowing that the depolarization depends on the distance from the point of injection, x, as given by the formula below, calculate the total capacitance of the cell membrane.

Vm(x) = Vr + (Vm(x=0)-Vr) ́ exp(-x/l), where l is the length constant.

Answer 1