Weng Xie-Chuan, Zheng Jian-Quan, Gai Xiao-Dan, Li Jin, Xiao Wen-Bin
Beijing Institute of Pharmacology & Toxicology, Beijing 100850, China.
Neurosci Res. 2004 Dec;50(4):493-9. doi: 10.1016/j.neures.2004.09.001.
Two types of acid-sensing ion channel (ASIC)-like currents in cultured rat hippocampal neurons were recorded and their characteristics were studied by using a whole-cell recording technique. The results revealed that the ASIC-like currents, induced by a quick drop of the extracellular pH, decayed with different time constants (tau) of 229 +/- 16 (Type I) and 1209 +/- 56 ms (Type II). The ASIC-like currents displayed different sensitivities to extracellular proton (pH0.5 was 6.17 +/- 0.04 for Type I and 5.70 +/- 0.07 for Type II) and amiloride, a specific ASIC channel blocker (IC50 was 1.19 +/- 0.37 microM for Type I and 0.14 +/- 0.02 microM for Type II). Among all the 360 recorded neurons, ASIC-like currents were induced in 314 neurons (87.2%). In the neurons expressing ASICs, Type I currents were evoked from 269 neurons (85.7%) and Type II currents were induced only from 45 neurons (14.3%). As these ASIC-like currents presented various electrophysiological and pharmacological properties, further experiments should be conducted to decipher the complex subunit composition of ASICs in the hippocampus.
采用全细胞膜片钳记录技术，记录并研究了培养的大鼠海马神经元中两种酸敏感离子通道（ASIC）样电流的特性。结果显示，由细胞外pH值快速下降诱发的ASIC样电流，以229±16（I型）和1209±56毫秒（II型）的不同时间常数（τ）衰减。ASIC样电流对细胞外质子表现出不同的敏感性（I型的pH0.5为6.17±0.04，II型为5.70±0.07），对特异性ASIC通道阻滞剂阿米洛利也表现出不同的敏感性（I型的IC50为1.19±0.37微摩尔，II型为0.14±0.02微摩尔）。在记录的360个神经元中，314个神经元（87.2%）诱发出了ASIC样电流。在表达ASIC的神经元中，269个神经元（85.7%）诱发出I型电流，只有45个神经元（14.3%）诱发出II型电流。由于这些ASIC样电流呈现出各种电生理和药理特性，因此应进一步开展实验以阐明海马体中ASIC复杂的亚基组成。
