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... > Dynamical rate property > Force property > Flow-driving potential > Electrodiffusional potential > Reversal potential

Preferred term

Reversal potential

http://www.irandoc.ac.ir/onto/irandoc-meta/Concept

Electrodiffusional potential

Obsolete

false

comment

The electrical potential across an electrodiffusion barrier that nullifies net ion diffusion

discussion

Here we distinguish two subclasses of membrane reversal potential that account for either (1) the Nernst potenial for a single ionic species whether or not it permeates the membrane as calculated by the Nernst equation that has terms the ratio of inner-to-outer ion concentrations (e.g., [Nai] / [Nao]) but no term of ionic permebility. That is, Nernst potentials are function only of the ion gradient (as a ratio) and not of ion permeability according to the Nernst equation. Thus, a Nernst reversal potential (for a single ion) can only be measured empirically under strict equilibrium conditions where membranes are permeable only to ions and there are no transmembrane ion currents, as from electrogenicl pumps. (2) the GHK potential (Goldman-Hodgkin-Katz potential) applies multiple ionic species and depends on their relative permeabilities as can be calculated using the GHK equation if all ion gradient ratios and relative permeabilities are known. The GHK reversal potential can be determined experimentally for a membrane as its resting membrane potential for which there is no net ion flux. See, amongst many others, for mathematical treatments: Hille, B. (2001). Ion Channels of Excitable Membranes. Sunderland, MA, USA, Sinauer Associates, Inc. http://www.physiologyweb.com/lecture_notes/resting_membrane_potential/resting_membrane_potential_nernst_equilibrium_potential.html

label

Reversal potential

prefixIRI

OPB:OPB_01271

پتانسیل معکوس

Persian

URI

http://www.irandoc.acir/onto/irandoc/OPB_01271

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