Contraction increases the T2 of muscle in fresh water but not in marine invertebrates
Contraction increases the T2 of muscle in fresh water but not in marine invertebrates
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DOI：
10.1002/nbm.702
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发表时间：
2001-05-01
影响因子：
2.9
通讯作者：
Wiseman, RW
中科院分区：
文献类型：
--
作者：
Meyer, RA;Prior, BM;Wiseman, RW
先前的研究表明，在哺乳动物骨骼肌中观察到的活动诱导的H-1-NMR横向弛豫时间（T-2）的增加与细胞内代谢物积累的渗透效应有关。通过比较淡水（小龙虾，Orconectes virilis）和两种渗透性海洋无脊椎动物（龙虾，Homarus americanus；扇贝，Argopecten concentricus）的肌肉在刺激后的T-2（在4.7 T时通过h -1核磁共振成像测量）和代谢物变化（通过p -31核磁共振波谱测量），验证了这一假设。刺激后龙虾尾肌细胞内pH值显著降低，而小龙虾尾和扇贝相内收肌细胞内pH值无显著降低。刺激后三种肌肉中磷酸甘氨酸与atp比值的下降是相似的。刺激后，小龙虾肌肉T-2从37 ms增加到43 ms (p < 0.02, n = 7)，龙虾肌肉T-2没有变化（32 ms, n = 7），扇贝肌肉T-2显著降低（40 ms至36 ms， p < 0.02, n = 11）。高自然渗透压的海洋无脊椎动物肌肉受到刺激后T-2不增加，这一观察结果与哺乳动物肌肉中T-2增加与渗透驱动的亚细胞间流体转移有关的假设是一致的。版权所有John Wiley & Sons， Ltd。
Previous studies suggest that the activity-induced increase in H-1-NMR transverse relaxation time (T-2) observed in mammalian skeletal muscles is related to an osmotic effect of intracellular metabolite accumulation. This hypothesis was tested by comparing T-2 (measured by H-1-NMR imaging at 4.7 T) and metabolite changes (measured by P-31-NMR spectroscopy) after stimulation in the muscles of a freshwater (crayfish, Orconectes virilis) vs two osmoconforming marine invertebrates (lobster, Homarus americanus; scallop, Argopecten concentricus). Intracellular pH significantly decreased after stimulation in the lobster tail muscle, but not in the crayfish tail or scallop phasic adductor muscles. The decrease in phosphoarginine-to-ATP ratio after stimulation was similar in the three muscles. Muscle T-2 increased from 37 to 43 ms (p < 0.02, n = 7) after stimulation in crayfish, but was unchanged in lobster muscle (32 ms, n = 7), and significantly decreased (from 40 to 36 ms, p < 0.02, n = 11) in scallop muscle. The observation that T-2 does not increase after stimulation in muscles of marine invertebrates with high natural osmolarity is consistent with the hypothesis that the T-2 increase in mammalian muscle is related to osmotically driven shifts of fluid between subcellular compartments. Copyright (C) 2001 John Wiley & Sons, Ltd.