Repolarization

In neuroscience, repolarization refers to the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential has changed the membrane potential to a positive value. The repolarization phase usually returns the membrane potential back to the resting membrane potential. The efflux of K⁺ ions results in the falling phase of an action potential. The ions pass through the selectivity filter of the K⁺ channel pore. There are several K⁺ channels that contribute to repolarization, including A-type channels, delayed rectifiers, and Ca²⁺-activated K⁺ channels.^[1]

Repolarization typically results from the movement of positively charged K⁺ ions out of the cell. The repolarization phase of an action potential initially results in hyperpolarization, attainment of a membrane potential, termed the afterhyperpolarization, that is more negative than the resting potential. Repolarization usually takes several milliseconds.^[2]

References

1. Purves D, Augustine GJ, Fitzpatrick D; et al., eds. (2001). Neuroscience (2. ed.). Sunderland, Mass: Sinauer Assoc. ISBN 0-87893-742-0.
2. Jeff Hardin; Gregory Paul Bertoni; Lewis J. Kleinsmith. Becker's World of the Cell. Benjamin-Cummings Publishing Company; December 2010. ISBN 978-0-321-71602-6. p. 389.

External links

• "Repolarization (Animation)". Psychology Department, Hanover College. Retrieved 18 May 2013.