自然界有很多非線性系統，在某些情況下，外加雜訊可以增強訊號傳導或偵測，這樣的理論稱為隨機共振(Stochastic Resonance). 目前已知大至冰河期週期預測，小至人眼視覺觀測，小腦平衡，螯蝦對於水流的偵測都發現這樣的現象，但在分子層次還未知。離子通道是存在細胞膜上的蛋白，其在神經訊號傳遞及細胞膜電位的穩定中扮演舉足輕重的角色，人體許多疾病也大多來自某種離子通道或受體失調，我們想知道類似的現象(stochastic resonance)會否在這樣的尺度看見。 經由微注射的方法把外來的RNA注射到南非爪蟾的卵內，經過一段時間(約一天)，卵的膜表面就會佈滿離子通道蛋白，再藉由電生理(electrophysiology)的方法來量測離子通道開合的活動，因為本實驗所使用的離子通道為電壓依賴型(voltage-dependent)，即可改變其細胞膜電位來控制其開啟或關閉，配合電位箝制的方法來量測通過離子通道電流之漲落。結果分析顯示外加雜訊的確能夠增強離子通道的訊噪比(signal-to-noise ratio)，且隨機共振的現象也可觀測到，暗示了外加雜訊的確可影響離子通道電導(conductance)的可能性。 The addition of noise to a system can enhance its ability of signal detection at some optimal noise level. This phenomenon, called stochastic resonance, is widely studied over the past two decades and observed in many fields including physics, chemistry, engineering, medicine and biology. However, the existence of stochastic resonance in the molecular level, the ion channel, still remains open. In this study, the ion channels of the cells are under investigation. Xenopus oocytes are injected with various concentrations of messenger RNA to express the ion channels over the membrane of the oocytes. The over-expressed ion channels used in our experiments are the Shaker-IR potassium channels, which are voltage-dependent ion channels. They can generally switch between different conformational states with voltage-dependent transition rates. The activities of the ion channels are recorded by the patch clamping technique. Data analysis shows qualitatively results that external random noise will enhance the efficiency of current transduction of the ion channels.
