頁籤選單縮合
| 題 名 | Changes in Membrane Cholesterol of Pituitary Tumor (GH[feb0]) Cells Regulate the Activity of Large-Conductance Ca[fec7]-Activated K[feb7] Channels |
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| 作 者 | Lin, Ming-wei; Wu, Adonis Z.; Ting, Wen-hung; Li, Ching-lin; Cheng, Kuo-sheng; Wu, Sheng-nan; | 書刊名 | 中國生理學雜誌 |
| 卷 期 | 49:1 民95.02 |
| 頁 次 | 頁1-13 |
| 分類號 | 415.149 |
| 關鍵詞 | Methy1-β-cyclodextrin; Cholesterol; Ca[fec7]-activated K[feb7] current; Large-conductance Ca[fec7]-activated K[feb7] channels; GH[feb0] cells; |
| 語 文 | 英文(English) |
| 英文摘要 | The effects of changes in membrane cholesterol on ion currents were investigated in pituitary G□ cells. Depletion of membrane cholesterol by exposing cells to methyl-β-cyclodextrin (MβCD), an oligosaccharide, resulted in an increase in the density of □ –activated □ current (□). However, no significant change in □ density was demonstrated in G□ cells treated with a mixture of MβCD and cholesterol. Cholesterol depletion with MβCD (1.5 mg/ml) slightly suppressed the density of voltage-dependent L-type □ current. In inside-out patches recorded from MβCD-treated cells, the activity of large-conductance □-activated □ (B□) channels was enhanced with no change in single-channel coundctance. In MβCD-treated cells, voltage-sensitivity of B□ channels was increased; however, no change in □-senstivity could be demonstrated. A negative correlation between adjacent closed and poen times in B□ chanels was observed in MβCD-treated cells. In inside-out patches from MβCD-treated cells, dexamethasone (30 μM) applied to the intracellular surface did not increase B□-channel activity, although caffeic acid phenethyl ester and cilotazol still pended its probability effectively. However, no modification in the activity of ATP-sensitive □ channels could be seen in MβCD-treated cells. Current-clamp recordings demonstrated that the cholesterol depletion maneuver with MβCD reduced the firing of action potentials. Therefore, the increase in B□-channel activity induced by membrane depletion may influence the functional activities of neurons or neuroendocrine cells if similar result occur in vivo. |
本系統中英文摘要資訊取自各篇刊載內容。