Niggli E, Rüdisüli A, Maurer P, Weingart R
Department of Physiology, University of Berne, Switzerland.
Am J Physiol. 1989 Feb;256(2 Pt 1):C273-81. doi: 10.1152/ajpcell.1989.256.2.C273.
Myocytes were isolated from adult guinea pig ventricles. Whole cell, tight-seal recording was employed to investigate the electrical properties of the junctional (nexal membrane) and nonjunctional membrane (sarcolemma) under the influence of n-alkanols (heptanol, octanol) and halothane. Studies of cell pairs with a double voltage-clamp approach showed that these agents give rise to a reversible electrical uncoupling. Examination of single myocytes with a single voltage-clamp method showed that these substances modify several sarcolemmal current systems. The slope conductance was reduced over the entire voltage range examined (-90 to +50 mV). The Ca2+ inward current (Isi) showed a decreased amplitude and an accelerated inactivation. The repriming of Isi remained unchanged. The steady-state inactivation of Isi was shifted by 2-3 mV toward more negative potentials. Optical measurements demonstrated an increase in sarcomere spacing at rest and a decrease during peak systolic shortening. The results suggest that n-alkanols and halothane exert their effects on membrane currents via incorporation into the lipid bilayer.
从成年豚鼠心室分离出心肌细胞。采用全细胞、紧密封接记录法，研究了正构烷醇（庚醇、辛醇）和氟烷影响下的连接膜（连接膜）和非连接膜（肌膜）的电特性。用双电压钳法对细胞对进行的研究表明，这些药物会引起可逆的电去耦联。用单电压钳法对单个心肌细胞的检查表明，这些物质会改变几种肌膜电流系统。在所研究的整个电压范围内（-90至+50 mV），斜率电导降低。Ca2+内向电流（Isi）幅度减小，失活加速。Isi的再激活保持不变。Isi的稳态失活向更负的电位偏移了2-3 mV。光学测量表明，静息时肌节间距增加，收缩期峰值缩短时减小。结果表明，正构烷醇和氟烷通过掺入脂质双层对膜电流发挥作用。
