TTX-Insensitive Sodium Current Develops in Adult Newt Pigment Epithelial Cells in Culture
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概要
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We cultured retinal pigment epithelial (RPE) cells dissociated from the adult newt eye and examined changes in the voltage-gated ionic currents with time in culture using whole-cell patch-clamp techniques. RPE cells allowed to adhere onto a concanavalin A-coated substrate began to flatten within 1-2 days and some of them started to divide on the 6th day of culturing. Freshly dissociated RPE cells exhibited only voltage-gated outward K^+ currents. Voltage-gated Na^+ currents associated with the initiation of immature action potentials were expressed in more than 50% of sufficiently stretched RPE cells before the first mitosis was observed. This fact may suggest that its expression is not coupled with the cell division. The Na^+ current was insensitive to the Na^+ channel blockers TTX and STX. Trichostatin A (TSA) arrested the cell division of cultured RPE cells reversibly. However, the Na^+ current expression was not blocked by this drug. Since TSA has been shown to act as an inhibitor of the cell cycle at G1 phase, the Na^+ current expression may be regulated by certain factors appearing between G0 and G1 phases before entering S phase. However, this does not mean that the current expression is directly coupled with the cell cycle, because about half of stretched cells do not express the current. We hypothesize that the Na^+ current expression and the presence of immature action potentials may represent a tendency of RPE cells to dedifferentiate towards embryonic neuroepithelial or more neuronal phenotypes in culture.
- 社団法人日本動物学会の論文
- 1996-02-15
著者
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Sakai Hideto
University Of Tsukuba Institute Of Biological Sciences
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Saito Takehiko
University Of Tsukuba Institute Of Biological Sciences