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pp.101-112
본 연구는 포유류인 통로의 존재 여부를 확인하기 위하여 수행되었다. 통로는 비흥분성 세포에서 용적변화와 pH 조절, 이온운반계 등에 중요한 역할을 수행하므로 활발한 세포분화가 이루어지는 난자의 생존과 기능에 필수적 통로 존재 여부를 확인하고자 하였다. 단일통로 전류를 기록하는 patch clamp 기법을 이용하였다. 세포외(pipette) 용액을 140 mM NaCl로 하고 세포내(bath) 용액을 70 mM, 140 mM, 280 mM NaCl로 바꾸
Chloride() channels play critical roles in cell homeostasis and its specific functions such as volume regulation, differentiation, secretion, and membrane stabilization. The presence of these channels have been reported in all kinds of cells and even in frog oocytes. These essential role of channels in cell homeostasis possibly play any role in egg homeostasis and in the early stage of development, however, there has been no report about the presence of channel in the mammalian oocyte. This study was performed to elucidate the presence of channels in hamster eggs. When allowing only to pass through the channel of the egg membrane by using impermeant cation such as N-methyl-D-glucamine(NMDG), single channel currents were recorded. These channel currents showed typical long-lasted openings interrupted by rapid flickering. Mean open was 4310.14 ms(n=9, at 50 mV). The open probability(Po) was decrease with depolarization. The current-voltage relation showed outward rectification. Outward slop conductance(325.4 pS, n=22) was steeper than the inward slop conductance(101.3 pS). Under the condition of symmetrical 140 mM NaCl, single channel currents were reversed at 0 mV(n=4). This reversal potential(Erev) was shifted from 0 mV at 140 mM concentration of internal NaCl(140 mM [Na+]i) to 9.80.5 mV(n=4) at 70 mM [Na+]i and 11.51.9 mV at 280 mM [Na+]i(n=4) respectively, strongly suggesting that these are single channel currents. To examine further whether this channel has pharmacological property of the channel, specific Cl channel blockers, IAA-94(Indanyloxyacetic acid-94) and DIDS(4, 4'-diisothiocyan ostillben- 2-2'disulfonic acid) were applied. IAA-94 inhibited the channel current in a dose-dependent manner and revealed a rapid and flickering block. From these electrophysiological and pharmacological resluts, we found the novel channel present in the hamster oocyte membrane. The first identification of channel in the hamster oocyte may give a clue for the further study on the function of channel in the fertilization and cell differentiation.
