Sokolova N A, Kuligina L D, Ashmarin I P
Nauchnye Doki Vyss Shkoly Biol Nauki. 1992(5):134-8.
In chronic experiments with rats during the exercises on a treadmill the ECG was registered and duration of the development of exhaustion was determined under control and under acute (1 mg/kg intraperitoneally 1 hour before the experiment) or chronic (1 mg/kg intraperitoneally, twice a day during 5 days) treatment with the opioid receptor antagonist naloxone. Chronic but not acute naloxone action resulted in increase of the fatiguability: the time of achievement of exhaustion decreased by 55.3% (P < 0.05). In this case the exhaustion developed at lower degree of heart rate than in control. Comparison of data obtained with the results of chronic treatment with the opioid antagonist permits to conclude that the chronic blockade increases the fatiguability to a great extent than chronic activation of opioid system. Possible mechanisms causing this difference are under discussion.
在对大鼠进行的慢性实验中，在跑步机上运动期间记录心电图，并在对照以及用阿片受体拮抗剂纳洛酮进行急性（实验前1小时腹腔注射1毫克/千克）或慢性（腹腔注射1毫克/千克，每天两次，持续5天）治疗的情况下，确定力竭发展的持续时间。纳洛酮的慢性而非急性作用导致易疲劳性增加：达到力竭的时间减少了55.3%（P<0.05）。在这种情况下，力竭发生时的心率低于对照。将获得的数据与用阿片拮抗剂进行慢性治疗的结果进行比较，可以得出结论，慢性阻断比阿片系统的慢性激活在更大程度上增加易疲劳性。正在讨论导致这种差异的可能机制。
