Key result
Elevated extracellular K+ shifts K+ current activation to more negative potentials in cultured mouse Schwann cells.
Why the study?
The influence of extracellular K+ concentration on the gating properties of K+ channels in cultured Schwann cells and its role in K+ homeostasis was not fully understood.
The control of extracellular K+ on the gating properties of K+ channels may enhance Schwann cell capability to take up K+ and maintain homeostasis in the peripheral nerve.
May inform Schwann cell K+ homeostasis models; leaves open any clinical relevance in human neuropathies.
In cultured Schwann cells, single-channel and whole-cell K+ currents can be activated by depolarizing the membrane to values more negative than -50 mV. In elevated extracellular K+ concentration ([K+]o), however, single-channel activity and whole-cell currents could be recorded at more negative potentials. Thus, the threshold of current activation was shifted to more negative potentials. This shift in the activation threshold was only observed with normal (50-60 mM) intracellular [K+] levels; it was not apparent when [K+]i was elevated to 145 mM. The control of [K+]o on the gating properties of K+ channels may serve to enhance the capability of the Schwann cell to take up [K+]o and thus may serve for [K+] homeostasis in the peripheral nerve.
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Verkhratsky et al. (1991) studied Cultured mouse Schwann cells. Elevated extracellular K+ concentration vs. Normal extracellular K+ concentration was evaluated on Threshold of K+ current activation. Elevated extracellular K+ concentration shifted the threshold of K+ current activation to more negative potentials in cultured mouse Schwann cells with normal intracellular K+ levels.
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