Hatfaludy S, Shansky J, Vandenburgh H H
Department of Pathology, Brown University, Providence, Rhode Island.
Am J Physiol. 1989 Jan;256(1 Pt 1):C175-81. doi: 10.1152/ajpcell.1989.256.1.C175.
Avian pectoralis muscle cells differentiated in vitro are mechanically stimulated by repetitive stretch-relaxations of the cell's substratum. Their metabolic response to mechanical activity is determined by measuring rates of [3H]deoxy-D-glucose uptake and lactate efflux. These two metabolic parameters show a similar biphasic response to mechanical stimulation. During the first 4-6 h of activity, [3H]deoxy-D-glucose uptake and lactate efflux increase 34 and 26%, respectively; at 8 and 24 h of activity, [3H]deoxy-D-glucose uptake and lactate efflux are no longer elevated relative to control values. With continued activity beyond 24 h, their rates are again significantly elevated (150 and 93% by 48 h, respectively). The long-term increases in [3H]deoxy-D-glucose uptake and lactate efflux occur independently of medium growth factors. Protein synthesis is required for the short-term increase in [3H]deoxy-D-glucose uptake, but muscle electrical activity is not required for either short- or long-term increases in [3H]deoxy-D-glucose uptake because both occur in the presence of tetrodotoxin. This new model system allows for the analysis of mechanically induced metabolic alterations in aneural skeletal muscle cells under the defined conditions of tissue culture.
体外分化的禽胸肌细胞通过细胞基质的重复拉伸-松弛进行机械刺激。通过测量[³H]脱氧-D-葡萄糖摄取率和乳酸流出率来确定它们对机械活动的代谢反应。这两个代谢参数对机械刺激表现出相似的双相反应。在活动的最初4-6小时内，[³H]脱氧-D-葡萄糖摄取和乳酸流出分别增加34%和26%；在活动8小时和24小时时，[³H]脱氧-D-葡萄糖摄取和乳酸流出相对于对照值不再升高。在活动持续超过24小时后，它们的速率再次显著升高（到48小时时分别升高150%和93%）。[³H]脱氧-D-葡萄糖摄取和乳酸流出的长期增加独立于培养基生长因子。蛋白质合成是[³H]脱氧-D-葡萄糖摄取短期增加所必需的，但[³H]脱氧-D-葡萄糖摄取的短期或长期增加都不需要肌肉电活动，因为两者都在河豚毒素存在的情况下发生。这个新的模型系统允许在组织培养的特定条件下分析无神经骨骼肌细胞中机械诱导的代谢改变。
