A.T. Still University School of Osteopathic Medicine, Mesa, AZ, USA.
Department of Cellular and Integrative Physiology at the University of Nebraska Medical Center, Omaha, NE, USA.
Adv Exp Med Biol. 2018;1071:129-136. doi: 10.1007/978-3-319-91137-3_16.
Physiological systems often display 24 h rhythms that vary with the light/dark cycle. Disruption of circadian physiological rhythms have been linked to the progression of various cardiovascular diseases, and advances in the understanding of these rhythms have led to novel interventions and improved clinical outcomes. Although respiratory function has been known to vary between the light and dark periods, circadian rhythms in breathing have been understudied in clinical conditions. In the current study, we have begun to assess light/dark variations in respiration in chronic heart failure (CHF), a condition associated with abnormal resting and chemoreflex breathing as well as exercise intolerance. CHF was induced using coronary artery ligation and verified using echocardiography. Sham animals underwent a thoracotomy without coronary artery ligation. Tidal volume, respiratory frequency, and minute ventilation were all determined by whole body plethysmography under resting conditions and in response to chemoreflex challenges during the light and dark periods. Light/dark differences in voluntary exercise were assessed using a running wheel. The sham control group showed light/dark differences in resting and chemoreflex breathing, as well as arterial pressure, and these effects were eliminated in the CHF group. Both groups completed more rotations on the running wheel during the dark period compared to during the light period. The data suggest that CHF disrupts cardiovascular and respiratory circadian rhythms.
生理系统通常显示出 24 小时的节律，这些节律随光/暗周期而变化。昼夜生理节律的破坏与各种心血管疾病的进展有关，对这些节律的认识的进步导致了新的干预措施和改善的临床结果。尽管呼吸功能在亮暗期间有所变化，但在临床情况下，呼吸的昼夜节律研究较少。在目前的研究中，我们开始评估慢性心力衰竭 (CHF) 中的呼吸亮暗变化，CHF 与异常静息和化学反射呼吸以及运动不耐受有关。通过冠状动脉结扎诱导 CHF，并通过超声心动图验证。假手术动物接受开胸术，但不进行冠状动脉结扎。在静息状态下和在光暗期对化学反射挑战时，通过全身 plethysmography 确定潮气量、呼吸频率和分钟通气量。使用跑步轮评估自愿运动的亮暗差异。假对照组在静息和化学反射呼吸、动脉压方面表现出亮暗差异，而 CHF 组则消除了这些影响。与亮期相比，两组在暗期都在跑步轮上完成了更多的旋转。数据表明 CHF 扰乱了心血管和呼吸的昼夜节律。
