中文摘要：

利用膜片钳技术之内面向外式，对培养2～24h不同类型的中华绒螯蟹（Erioeheirsinensis）血淋巴细胞表达的钙激活钾（KCa）通道进行种类鉴别和特征研究。结果表明：在高对称钾溶液（200mmol／L）中，只有小颗粒细胞表达大电导钙激活钾（BKCa）通道和中电导钙激活钾（IKCa）通道。其中BKCa通道电导为396pS，通道的开放活动表现为矩形方波。同一钳制电压下，当浴液中[Ca2＋1在0．3～3．0μmol／L范围内，通道开放概率和开放数目随Ca^2＋浓度增加而增加，当浴液中[Ca2＋]达到100．0gmol／L，通道开放受到抑制，表现明显的钙依赖性失活；当浴液中Ca^2＋浓度为3．0gmol／L，钳制电压分别为-40mV和-80mV时，通道平均开放时间分别为（0．03233±0．00741）S和（0．05585±0．01299）S（P〈0．01），平均开放概率分别为0．596±0．125和0．961±0．012（P〈0．01），说明通道开放具有电压依赖性。IKr。通道电导为88ps，开放活动也表现为矩形方波。当浴液中Ca2＋浓度为0．3、1．0μmol／L时，通道不开放；而Ca2＋浓度为3．0gmol／L时通道开放，说明通道具有明显的钙依赖性，钳制电压分别为-40mv和-80mv时，通道平均开放时间分别为（0．01736±0．00403）s和（0．02262±0．01616）s（P〉0．05），平均开放概率分别为0．699±0．065和0．790±0．114（p〉0．05），说明通道开放不具有明显的电压依赖性。药理学研究结果表明，40mmol／L四乙铵（TEA）灌流15min能完全阻断Kca通道活动。这提示钙激活钾通道在甲壳动物细胞免疫中发挥重要作用。

英文摘要：

Inside-out patch clamp technique was used to identify and characterize Calcium-activated potassium channels （Kca） from cultured Eriocheir sinensis haemocytes 2-24 h after plating. Calcium-activated potassium channels were observed in high symmetrical potassium solutions （200 mmol/L）. Only small granule cell （SG） expressed BKc, and IKca channels. The conductance of BKca channel was 396 pS with open rectangle waves. At constant potential, the open-rate and open-number of this channel were increased with [Ca2＋] from 0.3 to 3.0 μmol/L, but decreased when [Ca2＋] was increased up to 100.0μmol/L, manifesting Ca2＋-dependent inactivation of BKca channel. When the potential was held at -40 or -80 mV in the presence of 3.0 lamol/L [Ca2＋], the mean open-duration were （0.032 33±0.007 41） s or （0.055 85±0.012 99） s （P〈0.01）, respectively and the mean open probability were 0.596±0.125 or 0.961±0.012 （P〈0.01）, respectively, indicating that BKca channel is volt- age-dependent. The conductance of IKca channel was 88 pS, with open rectangle waves. IKca channel was open when [Ca2＋] was kept at up to 3.0 pmol/L, showing that IKca channel is Ca2＋-dependent. When the potential was held at -40 or -80 mV, the mean open-duration were （0.017 36±0.004 03）s or （0.022 62±0.016 16） s （P〉0.05）, re spectively and the mean open probability were 0.699±0.065 and 0.790±0.114 （P〉0.05）, respectively, indicating that IKca channel is not obviously voltage-dependent. In addition, the Calcium-activated potassium channel could be completely be blockaded by a 15-min perfusion of tetraethylammonium （40 mmol/L）, suggesting that the KCa channels have a pivotal function in cellular immunity of crustacean.