Waldman Brian M, Augustyniak Robert A, Chen Haiping, Rossi Noreen F
Department of Internal Medicine.
Department of Physiology, Wayne State University School of Medicine, Detroit, MI.
Integr Blood Press Control. 2017 Nov 29;10:41-51. doi: 10.2147/IBPC.S147122. eCollection 2017.
Spontaneous dynamic exercise promotes sympathoinhibition and decreases arterial pressure in two-kidney, one-clip (2K-1C) hypertensive rats. Renal sympathetic nerves stimulate renin secretion and increase renal tubular sodium reabsorption. We hypothesized that daily voluntary wheel running exercise by 2K-1C rats will decrease mean arterial pressure (MAP), plasma angiotensin II (Ang II), and aldosterone as well as normalize urinary sodium and potassium excretion independent of changes in glomerular filtration rate (GFR). Five-week-old male Sprague Dawley rats underwent sham clipping (Sham) or right renal artery clipping (2K-1C). Rats were randomized to standard caging (SED) or cages with running wheels (EX). After 12 weeks, rats were assigned to either collection of aortic blood for measurement of Ang II and aldosterone or assessment of inulin clearances and excretory function. Running distances were comparable in both EX groups. MAP was lower in 2K-1C EX vs 2K-1C SED rats (<0.05). Plasma Ang II and aldosterone were significantly higher in 2K-1C SED rats and decreased in 2K-1C EX rats to levels similar to Sham SED or Sham EX rats. Clipped kidney weights were significantly lower in both 2K-1C groups, but GFR and urine flow rates were no different from right and left kidneys among the four groups. Total and fractional sodium excretion rates from the unclipped kidney of 2K-1C SED rats were higher vs either Sham group (<0.05). Values in 2K-1C EX rats were similar to the Sham groups. Potassium excretion paralleled sodium excretion. These studies show that voluntary dynamic exercise in 2K-1C rats decreases plasma Ang II and aldosterone, which contribute to the lower arterial pressure without deleterious effects on GFR. The effects on sodium excretion underscore the impact of pressure natriuresis despite elevated plasma Ang II and aldosterone in sedentary 2K-1C rats. In contrast, potassium excretion is primarily regulated by circulating aldosterone and distal sodium delivery.
自发性动态运动可促进交感神经抑制,并降低两肾一夹(2K-1C)高血压大鼠的动脉血压。肾交感神经刺激肾素分泌并增加肾小管钠重吸收。我们假设,2K-1C大鼠每日进行自愿轮转跑步运动将降低平均动脉压(MAP)、血浆血管紧张素II(Ang II)和醛固酮水平,并使尿钠和钾排泄正常化,而与肾小球滤过率(GFR)的变化无关。5周龄雄性Sprague Dawley大鼠接受假夹闭手术(假手术组)或右肾动脉夹闭手术(2K-1C组)。大鼠被随机分为标准笼养组(SED)或带跑步轮的笼养组(EX)。12周后,大鼠被分配用于采集主动脉血以测量Ang II和醛固酮,或评估菊粉清除率和排泄功能。两个EX组的跑步距离相当。2K-1C EX组大鼠的MAP低于2K-1C SED组大鼠(<0.05)。2K-1C SED组大鼠的血浆Ang II和醛固酮显著更高,而2K-1C EX组大鼠的血浆Ang II和醛固酮降至与假手术SED组或假手术EX组大鼠相似的水平。两个2K-1C组大鼠的夹闭肾重量均显著更低,但四组大鼠的右肾和左肾的GFR及尿流率并无差异。2K-1C SED组大鼠未夹闭肾的总钠排泄率和分数钠排泄率均高于假手术组中的任一假手术组(<0.05)。2K-1C EX组大鼠的值与假手术组相似。钾排泄与钠排泄平行。这些研究表明,2K-1C大鼠的自愿动态运动可降低血浆Ang II和醛固酮水平,这有助于降低动脉血压,且对GFR无有害影响。对钠排泄的影响强调了压力性利钠作用的影响,尽管久坐的2K-1C大鼠血浆Ang II和醛固酮升高。相比之下,钾排泄主要受循环醛固酮和远端钠输送的调节。