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引用次数: 2
摘要
本章描述了来自心脏肌浆网和肌膜的整体膜通道的基本特性。在电压箝位条件下,通过分离的天然膜囊泡与预成型膜的融合,研究了通道与平面磷脂双层的融合。囊泡的融合速率可能受到许多因素的影响,包括预形成的双分子层中的二价阳离子和带负电荷的磷脂。哺乳动物心脏肌浆网含有一个单价阳离子选择通道,在500 mM K+的对称溶液存在下,其单通道电导约为150皮-西门子,保持电位范围为-60至+60 mV。通道处于开放状态的概率在正保持电位下高,在负保持电位下低。哺乳动物心脏肌膜包含至少3个K+选择性通道和1个Cl(-)选择性通道。
The measurement of cardiac membrane channels following their incorporation into phospholipid bilayers.
This chapter describes the basic properties of integral membrane channels from both cardiac sarcoplasmic reticulum and sarcolemma. Channels are studied, under voltage-clamp conditions, following their incorporation into planar phospholipid bilayers by fusion of isolated native membrane vesicles with preformed membranes. The rate of fusion of vesicles may be influenced by a number of factors including divalent cations and negatively charged phospholipids in the preformed bilayer. Mammalian cardiac sarcoplasmic reticulum contains a monovalent cation selective channel with a single-channel conductance of approximately 150 pico-Siemens in the presence of symmetrical solutions of 500 mM K+ at holding potentials ranging from -60 to +60 mV. The probability of the channel being in the open state is high at positive holding potentials and low at negative holding potentials. Mammalian cardiac sarcolemma contains at least three K+-selective channels and one Cl(-)-selective channel.