細胞膜電穿孔(MEP)在腦下垂體GH3細胞中是給予一外在的電場刺激下會對細胞膜產生相當大的導電性。本次研究中我們使用一種稱為honokiol (HNK)的中藥會對細胞膜電穿孔所導致的向胞內電流(IMEP)有何影響。利用膜箝制電生理技術，我們發現在GH3細胞中給予0.8 μM的HNK可以增加電穿孔所導致的電流大小，而隨後給予氯化鑭(LaCl3)或氯化錳(MnCl2)可逆轉HNK所產生的IMEP效果。若細胞已先加入10 μM的HNK，再接著給予同樣濃度的過氧基抑制劑(2,2’-azo-bis(2-amidonoprprane), AAPH)則不會再增加IMEP電流強度。此外若將細胞電極內加入1 μM的HNK，IMEP電流活性依然可被偵測到，測出單一離子通道電導為1.04 nS。我們進一步使用一種去趨勢波動分析法(detrended fluctuation analysis, DFA )來分析細胞在過極化(hyperpolarization)時的電流特性。另外當細胞在發生電穿孔電流前10秒前(initial IMEP ,(IPre))，DFA組成可分成短時間的延遲(short time-lag [1] )和長時間延遲(long time-lag [2])兩部份，兩者的交會點在第0.7秒鐘左右。1值為0.46±0.04 (n=7)，2值為0.62±0.05 (n=7)，顯現出與電穿孔電流訊號有某種相關特性。而在達到最大的電穿孔電流時，值(0.99±0.02，n=8)已無明顯的短、長時間延遲之區別。總結上述，我們實驗結果顯示，給予HNK至GH3細胞會對電穿孔II所導致的電流有增加作用，而造成電穿孔之現象是有可能可透過某些相關特性來預測的。

Membrane electroporation (MEP) had been identified in GH3 pituitary cells and known to produce a considerable increase in electrical conductivity of cell membrane by using an external electrical field. In this study we used a traditional Asian medicine, honokiol (HNK), to evaluate whether HNK exerts any effects on membrane electroporation-induced inward currents (IMEP). By using the patch-clamp recordings, we found that addition of HNK increased IMEP amplitude in a concentration-dependent manner with an EC50 value of 0.8 μM. A further application of LaCl3 or MnCl2 reversed HNK-induced IMEP. In the presence of HNK (10 μM), subsequent application of a water-soluble initiator of peroxyl radicals, 2,2’-azo-bis(2-amidonoprprane) (AAPH; 10 μM), did not increase IMEP further. As the electrode was filled with HNK (1 μM), the activity of IMEP was also detected with single-channel conductance of 1.04 nS. We applied the detrended fluctuation analysis (DFA) to analyze the current signals in response to large hyperpolarization. The DFA exponents from the current signals at 10 sec preceding the start of initial IMEP (IPre) in GH3 cells exhibited to be two components (short time-lag [1] and long time-lag [2]) with a crossover threshold of about 7 msec. The 1 value was 0.46±0.04 (n=7), whereas the 2 value with 0.62±0.05 (n=7) indicated the presence of long-term correlations of current signals. However, during maximal IMEP, the  value was linear and estimated to be 0.99±0.02 (n=8) with no clear crossover. Taken these findings together, our results indicate that HNK can contribute to MEP-induced channels to increase the amplitude of IMEP in GH3 cells. Furthermore, there is a correlated character of the electropore dynamics that may be allowed to predict the MEP process.

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