Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Babol University of Medical Sciences, Babol, Iran.
Pflugers Arch. 2012 Aug;464(2):175-82. doi: 10.1007/s00424-012-1121-z. Epub 2012 Jun 10.
The effect of nucleotides on single chloride channels derived from rat hepatocyte rough endoplasmic reticulum vesicles incorporated into bilayer lipid membrane was investigated. The single chloride channel currents were measured in 200/50 mmol/l KCl cis/trans solutions. Adding 2.5 mM adenosine triphosphate (ATP) and adenosine diphosphate (ADP) did not influence channel activity. However, MgATP addition inhibited the chloride channels by decreasing the channel open probability (Po) and current amplitude, whereas mixture of Mg(2+) and ADP activated the chloride channel by increasing the Po and unitary current amplitude. According to the results, there is a novel regulation mechanism for rough endoplasmic reticulum (RER) Cl(-) channel activity by intracellular MgATP and mixture of Mg(2+) and ADP that would result in significant inhibition by MgATP and activation by mixture of Mg(2+) and ADP. These modulatory effects of nucleotide-Mg(2+) complexes on chloride channels may be dependent on their chemical structure configuration. It seems that Mg-nucleotide-ion channel interactions are involved to produce a regulatory response for RER chloride channels.
研究了核苷酸对大鼠肝细胞粗面内质网囊泡来源的单层脂质膜中整合的单个氯离子通道的影响。在 200/50 mmol/l KCl 顺/反溶液中测量了单个氯离子通道电流。添加 2.5 mM 三磷酸腺苷 (ATP) 和二磷酸腺苷 (ADP) 不会影响通道活性。然而，MgATP 的添加通过降低通道开放概率 (Po) 和电流幅度来抑制氯离子通道，而 Mg(2+) 和 ADP 的混合物通过增加 Po 和单位电流幅度来激活氯离子通道。根据这些结果，细胞内 MgATP 和 Mg(2+)和 ADP 的混合物对粗面内质网 (RER) Cl(-)通道活性存在一种新的调节机制，MgATP 会显著抑制，而 Mg(2+)和 ADP 的混合物则会激活。核苷酸-Mg(2+)配合物对氯离子通道的这些调节作用可能取决于它们的化学结构构型。似乎 Mg-核苷酸-离子通道相互作用参与产生 RER 氯离子通道的调节反应。
