Wetzel P, Gros G
Zentrum Physiologie, Medizinische Hochschule Hannover, Germany.
J Exp Biol. 1998 Feb;201(Pt 3):375-84.
Isometric single-twitch force and intracellular Ca2+ transients were recorded simultaneously, using fura-2, from slow- and fast-twitch muscle fibres of the rat, mouse and Etruscan shrew Suncus etruscus. In the slow-twitch rat soleus, force half-relaxation time was three times longer than the 50% decay time of the fura-2 signal. In contrast, in the fast-twitch extensor digitorum longus muscles of all three animals, muscle relaxation preceded Ca2+ decay. It is proposed that this surprising property of fast-twitch muscles is due to their pCa-tension curve, which is shifted to the right compared with that of slow-twitch muscle.
使用fura-2同时记录了大鼠、小鼠和伊特鲁里亚鼩鼱（Suncus etruscus）慢肌纤维和快肌纤维的等长单收缩力和细胞内Ca2+瞬变。在大鼠慢肌比目鱼肌中，力的半松弛时间比fura-2信号的50%衰减时间长三倍。相比之下，在这三种动物的快肌趾长伸肌中，肌肉松弛先于Ca2+衰减。有人提出，快肌的这种惊人特性是由于其pCa-张力曲线，与慢肌相比，该曲线向右移动。
