Abstract:
:Potassium accumulation associated with outward membrane potassium current was investigated experimentally in myelinated fibers and analyzed in terms of two models-three-compartment and diffusion in an unstirred layer. In the myelinated fibers, as in squid giant axons, the three-compartment model satisfactorily describes potassium accumulation. Within this framework the average space thickness, theta, in frog was 5,900 +/- 700 A, while the permeability coefficient of the external barrier, PK, was (1.5 +/- 0.1) X 10(-2) cm/s. The model of ionic diffusion in an unstirred aqueous layer adjacent to the axolemma, as an alternative explanation for ion accumulation, was also consistent with the experimental data, provided that D, the diffusion constant, was (1.8 +/- 0.2) X 10(-6) cm/s and l, the unstirred layer thickness, was 1.4 +/- 0.1 micron, i.e., similar to the depth of the nodal gap. An empirical equation relating the extent of potassium accumulation to the amplitude and duration of depolarization is given.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Moran N,Palti Y,Levitan E,Stämpfli Rdoi
10.1016/S0006-3495(80)85028-4subject
Has Abstractpub_date
1980-12-01 00:00:00pages
939-54issue
3eissn
0006-3495issn
1542-0086pii
S0006-3495(80)85028-4journal_volume
32pub_type
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