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Expression of potassium channels during postnatal differentiation of rabbit Müller glial cells
Author(s) -
Bringmann A.,
Biedermann B.,
Reichenbach A.
Publication year - 1999
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1999.00706.x
Subject(s) - membrane potential , potassium channel , conductance , potassium , chemistry , electrophysiology , biophysics , bk channel , resting potential , patch clamp , endocrinology , medicine , biology , microbiology and biotechnology , neuroscience , physics , organic chemistry , condensed matter physics
The postnatal maturation of Müller glial cells from immature radial glial cells is accompanied by specific changes in the activity of distinct types of K + channels, as shown by whole‐cell and cell‐attached records on freshly isolated cells from retinae of young (postnatal days 1–30, P1–P30) and adult rabbits. (i) The density of inwardly rectifying currents, providing the main K + conductance in adult Müller cells, was very low (0.8 pA/pF) from P1 to P6 but increased rapidly thereafter until a relatively stable level of 11.0 pA/pF was established at P17. (ii) Transient (A‐type) K + currents were expressed in all immature cells at a high density (9.6 pA/pF). After P12, both the percentage of cells with A‐type currents and the peak amplitudes of the currents (2.8 pA/pF) declined. (iii) Delayed rectifying K + currents developed slowly until after P30. (iv) The postnatal maturation of radial glial cells was accompanied by a strong decrease in the activity of large‐conductance, Ca 2+ ‐activated K + channels, the open probability of which (measured at the resting membrane potential) decreased from 0.69 at P2–4 to 0.06 at P13–14. The developmental decrease of the activity of Ca 2+ ‐activated K + channels is assumed to be mainly caused by alteration of the resting membrane potential which developed from low values (–49 mV) at P1–6 to high adult values (–84 mV) after P13. The activity of each distinct type of K + channel investigated is differently modulated by developmental regulation. This may reflect different functional requirements of immature and mature Müller cells.