I'm wondering how long a neuron could continue to fire action potentials if all transporters (those using ATP) and co-transporters (those using other ion gradients) were blocked. Would it be several seconds, several minutes, an hour? I'm specifically wondering about mammalian cortical neurons.

I'd be interested in either empirical evidence or in back of the envelope biophysical calculations.

I'm guessing it is in the range of a minute since hypoxia can cause problems within a few minutes (and even that is buffered by the volume of blood).

Why I ask: Making a model. My simulation (based on biophysical assumptions) is losing it's potassium gradient faster than I would have expected.

Thanks in advanced. Really appreciate it.