Abstract:
:A novel way to model permeation through ionic channels is formulated. Our method does not require that equilibrium exists in the channel or at the channel interfaces. In addition, the potential profile does not need to be specified and the assumption of constant field across the membrane does not need to be made. Our formulation relies on statistical rate theory for its development and uses a form of the electrochemical potential which assumes that the ions are in solution. We show that the conductance and the degree of nonlinearity are dependent on the relative equilibrium exchange rates in the channel and at the interfaces. Nonlinear current-voltage plots can be obtained in symmetric solutions as well as a nonunity exponent for the Ussing flux ratio. Due to the dependence of the partition coefficient on solubility, it is highly unlikely that the intracellular and extracellular partition coefficients are the same. A manifestation of unequal partition coefficients is a current reversal at a membrane voltage that is different from the Nernst potential of the current-carrying ionic species.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Skinner FK,Ward CA,Bardakjian BLdoi
10.1016/S0006-3495(93)81095-6subject
Has Abstractpub_date
1993-08-01 00:00:00pages
618-29issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(93)81095-6journal_volume
65pub_type
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