Increased optical transparency associated with excitation–contraction coupling in voltage-clamped cut skeletal muscle fibres
Increased optical transparency associated with excitation–contraction coupling in voltage-clamped cut skeletal muscle fibres
复制标题
电压钳位切割骨骼肌纤维中与激发-收缩耦合相关的光学透明度增加
作者：
L. Kovács;L. Kovács;Martin F. Schneider
CONTRACTION of a skeletal muscle fibre is triggered by depolarisation of its transverse (T-) tubules1, which occurs physiologically with the spread of an action potential into the T-system2. The T-tubule depolarisation gives rise to calcium release3,4 from the adjacent but separate5,6 sarcoplasmic reticulum (SR). The released calcium binds to troponin, removing the inhibition of actin–myosin interaction and enabling contractile activity7. Little is known about the nature of the T-tubule–SR interaction. It has been suggested that movement of charged molecules or dipoles in the T-tubule membrane is the initial voltage-sensitive step in the chain of events leading from T-tubule depolarisation to SR calcium release8, and membrane charge displacement currents which may reflect such movements have been observed and characterised8–10. We report here a study of subsequent changes which may be related to calcium release.
