• 作者： 廖志飛; 張恆慈; 陳介甫
• 作者服務機構： 國立陽明醫學院藥理學科暨研究所; 國立中國醫藥研究所
• 中文摘要： 本研究使用雄性Sprague-Dawley大白鼠之離體肺臟及心臟標本，探討β型交感神經接器(BAR)之致效劑isoproter-enol (ISO)是否可引致這些器官組織上之BAR產生內進及漸減調節。結果顯示，在肺臟標本ISO可引致BAR內進且呈現與處理時間及濃度有關之現象。比較ISO在肺臟與心臟標本之作用，發現ISO (10〞M) 處理30分鐘後，於肺臟可觀察到顯著的BAR內進，但於心臟則未見明顯之變化。預處理高張蔗糖溶液（0.45-0.6M)30分鐘，可大半阻斷ISO在肺臟引致之BAR內進。以ISO (10μM) 或terbutaline (10μM) 處理3或12小時後，於肺臟及心臟標本均未見BAR數目有明顯變化，但在心臟標本則發現ISO處理12小時後可使放射性藥物[I]-iodocyanopindolol對BAR之解離常數(K)顯著增加。於蛋白質合成抑制劑cycloheximide (20 μg/ml, 12/ml 小時)存在下，則未見此種K變化，亦未見ISO引致BAR數目明顯變化。
• 英文摘要： Using isolated lung and heart preparations from male Sprague-Dawley'rats, this study characterizeswhether the β-adrenergic receptor (BAR) agonist isoproterenol (ISO) can induce internalization and down-regulation of BAR in these tissues. The results showed that ISO-induced BAR internalization was time- andconcentration-dependent in the lung preparations. When the lung and heart preparations were compared,however, the same ISO（10 μM,30 min) treatment only induced BAR internalization in the lung but notin the heart preparations. Pretreatment of hypertonic sucrose medium (0.45-0.6 M) for 30 min inhibitedabout 50% of ISO-induced BAR internalization in the lung preparations. Treatment of either ISO（10 μM)or terbutaline (10 μM) for 3 hr or 12 hr did not significantly decrease the number of BAR in both tissue pre-parations. However, ISO (10 μM，12 hr) increased the K value of the radioligand [I]-iodocyanopindololfor BAR in the heart homogenates. This ISO-induced K change was not observed in the presence of cy-cloheximide (20 μg/ml), a protein synthesis inhibitor. In the presence of cycloheximide (20 μg/ml), ISOalso did not decrease the BAR number in either tissue preparation.
• 中文關鍵字： β-adrenergic receptors; internalization; down-regulation; 0.45 M sucrose; rat lung; rat heart
• 英文關鍵字： --