Study on circadian changes in sympathetic tone in subtotal nephrectomized rats with heart failure

我们研究了慢性肾脏疾病(CKD)是否会改变心力衰竭(HF)大鼠自主神经功能的昼夜变化。大鼠接受了肾次全切除和外科手术诱发的心肌梗死，作为心肾综合征的潜在模型。清醒自由大鼠适应12h的明暗周期后，用仪表式无线遥测压力传感器连续记录24~48h的血压、心率和运动活动。在觉醒期间，有CKD的HF大鼠的舒张压变异性的低频成分比无CKD的HF大鼠更夸大。在慢性肾功能衰竭大鼠觉醒期间，通过每小时间歇性CO2暴露评估的高碳酸血症化疗敏感性一过性增加，提示中枢化疗敏感性可能与心肾综合征交感神经张力的夸大有关。

We studied whether chronic kidney disease (CKD) could alter circadian changes in autonomic function in rats with heart failure (HF). Rats underwent subtotal nephrectomy and surgically induced myocardial infarction as a potential model of cardiorenal syndrome. After acclimatization to a 12h light-dark cycle, blood pressure, heart rate and locomotor activity were continuously recorded for 24 - 48 hours in conscious, unrestrained rats by using instrumented radiotelemetry pressure transducer. During the awakening period, low frequency components of diastolic blood pressure variability, an index of sympathetic tone, were more exaggerated in HF rats with CKD than in HF rats without CKD. Hypercapnic chemosensitivity evaluated by hourly intermittent CO2 exposure was transiently increased during the awakening period in HF rats with CKD, suggesting that central chemosensitivity could be related to the exaggerated sympathetic tone in cardiorenal syndrome.