頁籤選單縮合
題 名 | Change of Potassium Current Density in Rabbit Corneal Epithelial Cells during Maturation and Cellular Senescence |
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作 者 | Chang, Shu-wen; Chang, Gwo-jyh; Su, Ming-jai; | 書刊名 | Journal of the Formosan Medical Association |
卷 期 | 105:1 民95.01 |
頁 次 | 頁7-16 |
分類號 | 364 |
關鍵詞 | Cellular senescence; Corneal epithelium; Maturation; Potassium current; |
語 文 | 英文(English) |
英文摘要 | Background: Voltage-gated potassium (K+) channels may participate in cellular developmental regulation, including cell differentiation, proliferation and apoptosis. This study investigated the change of K + current densities in corneal epithelial cells during maturation and cellular senescence. Methods: New Zealand white rabbits were divided into three age groups: newborn (</= 7 days old, n = 18); young (8-12 weeks old, n = 59); and adult (20-28 weeks old, n = 16). Rabbit corneal epithelial cells were subdivided into the following three groups: small cells with capacitance < 6.0 pF; medium cells with capacitance 6.0-10.0 pF; and large cells with capacitance > 10.0 pF. Using a whole-cell clamp technique, K+ current was recorded and current densities were calculated. Differences in K+ current densities among newborn, young and adult rabbits, as well as differences among small, medium and large cells, were analyzed. Results: We delineated two types of cells manifesting different amplitudes of depolarization-activated K+ outward currents. The averaged current density of type 1 response cells was significantly larger than that of type 2 cells in newborn, young, and adult groups. For newborn epithelial cells, the depolarization-gated outward K+ current density decreased from small to medium to large cells (p = 0.049, at a membrane potential of 140 mV). A similar pattern of change in current density was also delineated for these cell sizes in young and adult rabbit corneal cells (p < 0.001 for both young and adult rabbits). An increase in depolarization-gated outward K+ current density was also delineated from newborn to young to adult rabbits (p < 0.001, p < 0.001 and p < 0.006 for small, medium and large cells, respectively, at a membrane potential of 140 mV). Conclusions: Corneal epithelial cells expressed K+ channel densities that were distinct from basal to superficial cells and from newborn to adult rabbits. |
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