Yamamoto D, Suzuki N
Laboratory of Neurophysiology, Mitsubishi-Kasei Institute of Life Sciences, Tokyo, Japan.
Am J Physiol. 1989 Mar;256(3 Pt 1):C683-7. doi: 10.1152/ajpcell.1989.256.3.C683.
Tetraethylammonium (TEA) ions blocked the unitary currents through the delayed rectifier potassium channels of Drosophila neurons from the cytoplasmic side of inside-out membrane patches by two distinct mechanisms. First, TEA attenuated the single-channel conductance, probably by producing very rapid block-unblock reactions at the inner mouth of the potassium pore. Second, TEA markedly enhanced the slow inactivation, making the incidence of channel openings highly nonrandom; blank traces with no channel openings during repetitive depolarizations showed a significant tendency to be clustered in the presence of TEA. This second action accounts for almost half of the reduction of average current produced by 10 mM internal TEA.
四乙铵（TEA）离子通过两种不同机制从内向外膜片的细胞质侧阻断果蝇神经元延迟整流钾通道的单位电流。首先，TEA可能通过在钾通道孔的内口产生非常快速的阻断-解阻断反应来减弱单通道电导。其次，TEA显著增强了缓慢失活，使通道开放的发生率变得高度非随机；在重复去极化期间没有通道开放的空白记录显示，在存在TEA的情况下有明显的聚集趋势。第二种作用几乎占10 mM内部TEA产生的平均电流降低的一半。
