对含有缝隙连接通道的细胞膜进行膜片钳记录。
Patch clamp recordings from membranes which contain gap junction channels.
作者信息
Brink P R, Fan S F
机构信息
Department of Anatomical Sciences, School of Medicine, State University of New York, Stony Brook 11794.
出版信息
Biophys J. 1989 Sep;56(3):579-93. doi: 10.1016/S0006-3495(89)82705-5.
The septal membranes of the median and lateral giant axons of earthworm, which contain gap junctions, were exposed by cutting one segment of the cord. Patch recordings were obtained from the exposed cytoplasmic side of the septum. Seal resistances ranged from 2 to 15 G omega. The patch could be excised (detached) or left attached to the whole cell. Two types of channels were observed. One type was blocked by tetraethylammonium (TEA) or Cs+ and had a unitary conductance of 30-40 pS. It appears to be a K+ channel. The other channel type had a unitary conductance of 90-110 pS and was unaffected by TEA+ or Cs+. In the detached configuration the channel was shown to conduct Cs+, K+, Na+, TMA+, Cl- and TEA+ even in the presence of 2 mM Zn2+, 1 mM Ni2+, 1 mM Co2+, and 4 mM 4-aminopyridine. The conductance ratios relative to K+ were 1.0 for Cs+, 0.84 for Na+, 0.64 for TMA+, 0.52 for Cl- and 0.2 for TEA+. The channel appears to be voltage insensitive whether monitored in detached or attached recording mode. Both H+ and Ca2+ reduce the probability of opening. Thus, the 100 pS channel has many of the properties expected of a gap junction channel.
蚯蚓正中巨轴突和外侧巨轴突的隔膜含有缝隙连接，通过切断一段脊髓将其暴露出来。从暴露的隔膜细胞质侧进行膜片钳记录。封接电阻范围为2至15 GΩ。膜片可以被切除（分离）或保留与全细胞相连。观察到两种类型的通道。一种类型被四乙铵（TEA）或Cs⁺阻断，单位电导为30 - 40 pS。它似乎是一种钾通道。另一种通道类型单位电导为90 - 110 pS，不受TEA⁺或Cs⁺影响。在分离状态下，即使存在2 mM Zn²⁺、1 mM Ni²⁺、1 mM Co²⁺和4 mM 4 - 氨基吡啶，该通道仍能传导Cs⁺、K⁺、Na⁺、TMA⁺、Cl⁻和TEA⁺。相对于K⁺的电导比，Cs⁺为1.0，Na⁺为0.84，TMA⁺为0.64，Cl⁻为0.52，TEA⁺为0.2。无论在分离记录模式还是全细胞记录模式下监测，该通道似乎对电压不敏感。H⁺和Ca²⁺都降低通道开放的概率。因此，100 pS的通道具有许多缝隙连接通道预期的特性。
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