Neural firing usually occurs in the form of spike series. Several action potentials are happening in a quick succession. Whereas Na/K pumps (and other pumps) restore ion gradients to allow processes that take place during an action potential.
Now my question is, what would happen if we completely blocked these pumps and immediately after, we started exciting a neuron? Would the neuron be able to fire a few times before losing the gradients? Or, would one single spike completely diminish the gradients and without restoration by pumps, a second AP would be impossible?