Mainwood G W, Totosy De Zepetnek J
Muscle Nerve. 1985 Nov-Dec;8(9):774-82. doi: 10.1002/mus.880080906.
The total creatine content of rat extensor digitorum longus (EDL) muscles is reduced from 26.7 mumol X g-1 to 5.2 mumol X g-1 after 4 weeks on a diet containing beta-guanidinopropionate. The resting muscles of these animals contain only 5% of the normal creatine phosphate and about 30% of the normal adenosine triphosphate (ATP). Isometric twitch and brief tetanic responses are not significantly different from normal. However, following a 1-second tetanus, the normal twitch potentiation (+80%) is reversed in depleted muscles (-40%). The initial suppression lasts 1-2 seconds and is followed by a small delayed potentiation (+25%). Relaxation rate, which is normally increased following a tetanus, is considerably reduced in depleted muscles. Reversal of potentiation appears to be due to a suppression of twitch activation. The suppression may result from a transient fall in delta GATP, which is thought to be a critical parameter in the uptake of Ca++ by the sarcoplasmic reticulum (SR).
在食用含β-胍基丙酸的日粮4周后，大鼠趾长伸肌（EDL）的总肌酸含量从26.7 μmol·g-1降至5.2 μmol·g-1。这些动物的静息肌肉中仅含有正常磷酸肌酸的5%和约30%的正常三磷酸腺苷（ATP）。等长收缩和短暂强直反应与正常情况无显著差异。然而，在1秒强直刺激后，正常的收缩增强（+80%）在肌酸耗尽的肌肉中出现逆转（-40%）。最初的抑制持续1 - 2秒，随后是轻微的延迟增强（+25%）。通常在强直刺激后会增加的舒张速率，在肌酸耗尽的肌肉中显著降低。收缩增强的逆转似乎是由于收缩激活的抑制。这种抑制可能是由于ΔGATP的短暂下降导致的，ΔGATP被认为是肌浆网（SR）摄取Ca++的关键参数。
