Tatsumi T, Asayama J, Yamahara Y, Miyazaki H, Inoue M, Omori I, Inoue D, Nakagawa M
Second Department of Medicine, Kyoto Prefectural University of Medicine, Japan.
Jpn Heart J. 1991 May;32(3):363-71. doi: 10.1536/ihj.32.363.
The effects of hypoxia and reoxygenation on regular contractions and postrest contractions (PRC) of papillary muscle of rats were studied. Isometric tension was measured during two cycles of hypoxia and reoxygenation. Trains of 80 externally continuous stimulations at 40/min were applied. PRCs were evoked by a stimulus train after a 60 sec resting interval. After 90 min of hypoxia (the first hypoxia period), regular contractions and PRCs decreased to 5.6 +/- 2.0% and 23.4 +/- 2.4% of baseline values, respectively (p less than 0.001; n = 18). After 90 min of reoxygenation, the recovery of the PRCs (44.4 +/- 3.4%) was better than that of the regular contractions (23.3 +/- 3.3%) (p less than 0.01; n = 18). After 30 min of hypoxia (the second hypoxic period), regular contractions and PRCs decreased to 2.2 +/- 0.6% and 13.6 +/- 1.6% of baseline values, respectively (p less than 0.001; n = 18). However, the recovery from the second hypoxic injury was not significant for either regular contractions or PRCs. The % diastolic tension, which was normalized to the baseline for regular contractions, increased to 113.2 +/- 6.9% and 133.6 +/- 8.4% at the end of the first and the second hypoxic periods, respectively. There was statistically significant correlation between the % diastolic tension and the % hypoxic injury of PRCs (p less than 0.002; n = 18). There was no significant relationship between % diastolic tension and % hypoxic injury of regular contractions. There was no statistically significant correlation between % diastolic tension and % recovery from the hypoxic injury of either regular contractions or PRCs.(ABSTRACT TRUNCATED AT 250 WORDS)
研究了缺氧和复氧对大鼠乳头肌正常收缩和静息后收缩（PRC）的影响。在两个缺氧和复氧周期中测量等长张力。以40次/分钟的频率施加80次外部连续刺激的序列。在60秒的静息间隔后，通过刺激序列诱发PRC。缺氧90分钟（第一个缺氧期）后，正常收缩和PRC分别降至基线值的5.6±2.0%和23.4±2.4%（p<0.001；n=18）。复氧90分钟后，PRC的恢复（44.4±3.4%）优于正常收缩的恢复（23.3±3.3%）（p<0.01；n=18）。缺氧30分钟（第二个缺氧期）后，正常收缩和PRC分别降至基线值的2.2±0.6%和13.6±1.6%（p<0.001；n=18）。然而，第二次缺氧损伤后的恢复对于正常收缩和PRC均不显著。相对于正常收缩的基线进行归一化的舒张期张力百分比，在第一个和第二个缺氧期末分别增加到113.2±6.9%和133.6±8.4%。PRC的舒张期张力百分比与缺氧损伤百分比之间存在统计学显著相关性（p<0.002；n=18）。正常收缩的舒张期张力百分比与缺氧损伤百分比之间无显著关系。舒张期张力百分比与正常收缩或PRC缺氧损伤恢复百分比之间无统计学显著相关性。（摘要截断于250字）
