Acid-Sensitive Outwardly Rectifying Anion Channels in Human Erythrocytes

作者：Kucherenko Yuliya V; Moersdorf Daniel; Lang Florian^*

来源：Journal of Membrane Biology, 2009, 230(1): 1-10.

DOI：10.1007/s00232-009-9179-z

• Erythrocyte
• Patch clamp
• Cl(-) channel
• Low extracellular pH
• Osmolarity

Acid-sensitive outwardly rectifying anion channels (ASOR) have been described in several mammalian cell types. The present whole-cell patch-clamp study elucidated whether those channels are expressed in erythrocytes. To this end whole-cell recordings were made in human erythrocytes from healthy donors treated with low pH and high osmotic pressure. When the pipette solution had a reduced Cl(-) concentration, treatment of the cells with Cl(-)-containing normal and hyperosmotic (addition of sucrose and polyethelene glycol 1000 [PEG-1000] to the Ringer) media with low pH significantly increased the conductance of the cells at positive voltages. Channel activity was highest in the PEG-1000 media (95 and 300 mM PEG-1000, pH 4.5 and 4.3, respectively) where the current-voltage curves demonstrated strong outward rectification and reversed at -40 mV. Substitution of the Cl(-)-containing medium with Cl(-)-free medium resulted in a decrease of the conductance at hyperpolarizing voltages, a shift in reversal potential (to 0 mV) and loss of outward rectification. The chloride currents were inhibited by chloride channels blockers DIDS and NPPB (IC(50) for both was similar to 1 mM) but not with niflumic acid and amiloride. The observations reveal expression of ASOR in erythrocytes.

• 出版日期2009-7