Mitogenesis in a variety of tissues is known to be inhibited by K+ channel blockers such as tetraethylammonium (TEA) and 4-aminopyridine (4-AP). Using radiolabeled thymidine as a proliferation index we have examined what role, if any, specific K+ channels have in cultured Schwann cells that have bee
Ion channels in cultured adult human schwann cells
β Scribed by Dr. James G. McLarnon; Seung U. Kim
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 686 KB
- Volume
- 4
- Category
- Article
- ISSN
- 0894-1491
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β¦ Synopsis
Single channel currents have been recorded from cultured adult human Schwann cells. In both cell-attached and -excised (inside-out) patches, openings from a high-conductance (360 pS) channel were observed; measurements of the zero-current potential indicated that the channel was predominantly selective for chloride. Depolarizing and hyperpolarizing voltage steps activated the anion channel, which subsequently reverted to a closed state even in the presence of the maintained step. A second channel, with a conductance near 20 pS and with a current amplitude that increased with patch hyperpolarization, passed inward K+ currents in both cell-attached and inside-out patches. The mean open times for this channel were near 20 ms at the cell resting potential and decreased with patch hyperpolarization. The presence of these anion and cation selective channels in the human Schwann cell membrane would be consistent with a role for the cells in the regulation of extracellular K+.
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