Li Na, Guan Yue, Zhang Li, Tian Yanming, Zhang Yi, Wang Sheng
Department of Physiology, Hebei Medical University, Shijiazhuang 050017, Hebei, People's Republic of China.
Department of Physiology, Medical College, Hebei University, Baoding 071000, Hebei, People's Republic of China.
Chin J Physiol. 2016 Aug 31;59(4):210-7. doi: 10.4077/CJP.2016.BAF444.
Baroreflex function plays a critical role in the maintenance of cardiovascular homeostasis and is impaired in different types of hypertension in both human and animals. Chronic intermittent hypobaric hypoxia (CIHH) facilitates baroreflex in anesthetized rats. The aim of present study was to investigate the effect of CIHH on arterial blood pressure (ABP) and baroreflex function in renal vascular hypertension (RVH) rats. Adult male Sprague-Dawley rats were randomly divided into four groups: Sham-operated (SHAM), RVH, CIHH treatment (CIHH), and RVH plus CIHH (RVH+CIHH) groups. RVH was induced by 2-kidney-1-clip method. CIHH rats experienced 28-day (6 h per day) hypobaric hypoxia simulating 5,000 m altitude in hypobaric chamber. Renal sympathetic nerve activity (RSNA), ABP and heart rate (HR) were recorded. Baroreflex was elicited by intravenous infusion of phenylephrine (PE, 25 μg/kg) and sodium nitroprusside (SNP, 10 μg/KG), respectively. Baroreflex curves were plotted by using RSNA or HR v.s. mean arterial pressure (MAP). The systolic ABP measured by tail-cuff method was significantly higher in RVH rats compared with SHAM rats. Furthermore, RSNA-MAP baroreflex curves were shifted to the right and upward with a decrease in baroreflex gain (Gmax) in RVH rats. CIHH treatment significantly decreased systolic ABP in RVH rats to the level in SHAM rats and shifted RSNA-MAP baroreflex curves to the left and downward with a normalized Gmax. These data suggest that CIHH treatment produces an anti-hypertensive effect in RVH rats, likely due to facilitating baroreflex function. Thus, CIHH represents a novel potential therapeutics to treat hypertension.
压力反射功能在维持心血管稳态中起着关键作用，在人类和动物的不同类型高血压中均受损。慢性间歇性低压低氧（CIHH）可促进麻醉大鼠的压力反射。本研究的目的是探讨CIHH对肾血管性高血压（RVH）大鼠动脉血压（ABP）和压力反射功能的影响。成年雄性Sprague-Dawley大鼠随机分为四组：假手术（SHAM）组、RVH组、CIHH治疗（CIHH）组和RVH加CIHH（RVH+CIHH）组。采用二肾一夹法诱导RVH。CIHH大鼠在低压舱中经历28天（每天6小时）模拟海拔5000米的低压低氧。记录肾交感神经活动（RSNA）、ABP和心率（HR）。分别通过静脉注射去氧肾上腺素（PE，25μg/kg）和硝普钠（SNP，10μg/KG）诱发压力反射。使用RSNA或HR对平均动脉压（MAP）绘制压力反射曲线。与SHAM大鼠相比，RVH大鼠通过尾袖法测量的收缩期ABP显著更高。此外，RVH大鼠的RSNA-MAP压力反射曲线向右上方移位，压力反射增益（Gmax）降低。CIHH治疗显著降低RVH大鼠的收缩期ABP至SHAM大鼠水平，并使RSNA-MAP压力反射曲线向左下方移位，Gmax恢复正常。这些数据表明，CIHH治疗对RVH大鼠产生降压作用，可能是由于促进了压力反射功能。因此，CIHH代表了一种治疗高血压的新型潜在疗法。
