Consider a mammalian neuron with the following properties:

[K⁺]_out = 4mM [Na⁺]_out = 140mM

[K⁺]_in = 130mM [Na⁺]_in = 15mM

gK = 18.7S gNa = 4S

Calculate the equilibrium potentials for K⁺ and Na⁺ at body temperature (37C).

At rest, the relative permeability of K⁺ : Na⁺ is 20 : 1. Using the GHK equation, calculate the rest potential of this neuron at 37C.

At rest, which ionic current has the largest driving force?

When this neuron is stable at its rest potential, which direction (entering or leaving the cell) is each ionic current moving?

Calculate the specific ionic currents (INa⁺, IK⁺) that are flowing at rest potential. Do these values make sense? Explain.

Imagine that an extremely powerful K⁺ channel blocker is added to this neuron. Predict what might happen to the rest potential, using your calculations above and sound logic as rationale for your predictions. Make a prediction about the neurobiological/functional consequences of the K⁺ channel blocker.