Читать книгу Neurobiology For Dummies - Frank Amthor - Страница 105

The resting potential is the voltage across the membrane when the neuron is not strongly driven by excitatory inputs. It’s established by ionic gradients and charge imbalances that occur because the sodium-potassium transporter pumps are constantly working. At this resting potential in most neurons, some leakage current flows through open chloride channels and a small conductance of potassium channels.

If we use the Goldman–Hodgkin–Katz equation (refer to the “Goldman–Hodgkin–Katz equation” section, earlier in this chapter) to solve for the voltage across the membrane given the sodium, potassium, and chloride permeabilities, we get a resting potential of about –65 mV. (In most cells, this value varies somewhat across neurons.) Because chloride passively distributes its concentration across the membrane — due to diffusion and electric field forces created by sodium-potassium pumps — we find that the resting membrane potential is due mostly to the resting potassium conductance. Opening sodium channels that depolarize the inside of the neuron change all this drastically.