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In this paper, membrane current properties of the fully-grown oocytes from toad, Bufo bufo gargarizans, were studied byusing two-microelectrode voltage clamp technique. Axion of adult female toad was destroyed, and then ovarian lobes containing oocytesin stage I to VI were removed and incubated in Ca2+-free ND96 solution with collagenase (1.5 mg/ml) for 1 h. Subsequently, the oocyteswere washed in Ca2+-free ND96 solution for 10 min to completely remove the follicular layer. For the experiments only the oocytes instage V and VI were selected and used during 1 to 5 d. The membrane was depolarized from a holding potential of -80 mV to +60 mVin 10 mV step. It was found that a sustained outward current was elicited by depolarization. Potassium channel blockers(tetraethylammonium chloride, TEA, 10 mmol/L and 4-aminopyridine, 4-AP, 10 mmol/L) reduced the outward current to (23.4±0.72)%of the maximum. However, further addition of chloride channel blocker (5-nitro-2,3-phenypropylamino benzoate, NPPB, 30 μmol/L)could almost completely block the outward current to (2.1±0.08)% of the maximum. In the presence of TEA and 4-AP, removal of entracellularCa2+ or adding verapamil (40 μmol/L), could also reduce the outward current to (2.2±0.04)% and (3.1±0.15)% of the maximum, respectively.It is concluded that calcium-dependent chloride channels exist in plasma membrane of Bufo bufo gargarizans oocytes, besides potassiumchannels.