Cholesterol influences potassium currents in inner hair cells isolated from guinea pig cochlea

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• 作者：Takashi Kimitsuki ; ^{kimitsuki@kyushu-ctr-hsp.com}
• 关键词：Cochlea ; Inner hair cell ; Potassium current ; Cholesterol ; MβCD
• 刊名：Auris Nasus Larynx
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：44
• 期：1
• 页码：46-51
• 全文大小：828 K
• 卷排序：44

文摘

There is a correlation between serum hyperlipidemia and hearing loss. Cholesterol is an integral component of the cell membrane and regulates the activity of ion channels in the lipid bilayer. The aim of this study was to investigate the effects of cholesterol on the potassium currents in IHCs by using the cholesterol-depleting drug, MβCD, and water-soluble cholesterol.MethodsIHCs were acutely isolated from a mature guinea-pig cochlea and potassium currents were recorded. MβCD and water-soluble cholesterol were applied to IHCs under pressure puff pipettes.ResultsIHCs showed outwardly rectifying currents (IK,f and IK,s) in response to depolarizing voltage pulses, with only a slight inward current (IK,n) when hyperpolarized. In 10 mM MβCD solutions, the amplitude of outward K currents reversely decreased; however, fast activation kinetics was preserved. In contrast, in solution of 1 mM water-soluble cholesterol, the amplitude of outward K currents reversely increased. At the membrane potential of +110 mV, relative conductances were 0.87 ± 0.07 and 1.18 ± 0.11 in MβCD solutions and cholesterol solutions, respectively.ConclusionThe amplitude of K currents in isolated IHCs was reversely changed by cholesterol-depleting drug and water-soluble cholesterol. These results demonstrated the possibility of the involvement of IHC function in hyperlipidemia-induced inner ear disorders.