Weicker H, Hageloch W, Luo J, Müller D, Werle E, Sehling K M
Department of Sports Medicine and Pathophysiology, University of Heidelberg.
Int J Sports Med. 1990 May;11 Suppl 2:S68-77. doi: 10.1055/s-2007-1024857.
The purine nucleotides, phosphocreatine (PCr), ammonia, and lactic acid were investigated in skeletal muscles of rats with prominent type I, type IIa, type IIb fibers, and the heart after exhaustive and endurance swimming tests. ATP, ADP, AMP, IMP, and PCr were determined by HPLC with UV detection in controls after maximal and endurance training for 6 weeks with or without a respective final test and also after final exhaustive or endurance test without preceding training. The swimming time in these tests was longer with than without training. A pronounced ATP decrease and a large increase in IMP, up to 4.9 mumol/g wet weight, were found in type IIb fibers after the maximal final test without preceding training. Compared with skeletal muscle, the IMP concentration in the heart was significantly lower after all exercise bouts, even though after maximal exercise AMP augmentation was highest, ATP reduction was greatest, and energy charge was lowest. The difference between the heart and skeletal muscle in the production of IMP indicates that despite AMP and ADP accumulation, myoadenylate deaminase (MAD) activity in the heart is considerably lower than in skeletal muscle, especially in type IIb fibers. The smaller amount of MAD per tissue, and also the different MAD isozyme pattern of the heart as reported in the literature, may be attributed to lower activation. The difference between MAD activation of the soleus muscle and of the iliacus muscle, both consisting predominantly of type I fibers, suggests that MAD activity may be influenced by biochemical demand and oxygen supply, varying with the anatomical localization. Even though ammonia and lactic acid were highly correlated, it is questionable whether the H+ ion increase due to the lactate accumulation itself triggers MAD activation, as has been found for AMP and ADP in skeletal muscle.
在进行力竭性和耐力性游泳测试后，对具有明显的I型、IIa型、IIb型纤维的大鼠骨骼肌以及心脏中的嘌呤核苷酸、磷酸肌酸（PCr）、氨和乳酸进行了研究。在进行6周的最大强度训练和耐力训练（有或无相应的最终测试）后，以及在无前期训练的最终力竭性或耐力性测试后，通过高效液相色谱法（HPLC）结合紫外检测法测定对照组中的三磷酸腺苷（ATP）、二磷酸腺苷（ADP）、一磷酸腺苷（AMP）、次黄嘌呤核苷酸（IMP）和磷酸肌酸（PCr）。在这些测试中，有训练组的游泳时间比无训练组更长。在无前期训练的最大强度最终测试后，IIb型纤维中出现了明显的ATP下降以及IMP大幅增加，高达4.9微摩尔/克湿重。与骨骼肌相比，在所有运动试验后，心脏中的IMP浓度均显著较低，尽管在最大强度运动后AMP增加幅度最大、ATP减少幅度最大且能量电荷最低。心脏和骨骼肌在IMP产生方面的差异表明，尽管存在AMP和ADP积累，但心脏中的肌腺苷酸脱氨酶（MAD）活性明显低于骨骼肌，尤其是在IIb型纤维中。每个组织中MAD含量较少，以及文献报道的心脏中不同的MAD同工酶模式，可能归因于较低的激活程度。比目鱼肌和髂腰肌均主要由I型纤维组成，二者在MAD激活方面的差异表明，MAD活性可能受生化需求和氧气供应的影响，并随解剖定位而变化。尽管氨和乳酸高度相关，但乳酸积累本身导致的H⁺离子增加是否像在骨骼肌中发现的AMP和ADP那样触发MAD激活，仍存在疑问。
