Contribution of the Na(+)-K+ pump to membrane potential in familial periodic paralysis.

The possibility has been raised that in familial periodic paralysis, the relatively large depolarization of the muscle fiber membrane seen during periods of paralysis might be attributable to a reduction in activity of the electrogenic Na(+)-K+ pump. The theoretical analysis presented here shows that although such hypotheses are qualitatively correct, the quantitative contribution of the electrogenic pump is too small to account entirely for the changes in membrane potential observed between the paralytic and interictal states.