Gross V, Lippoldt A, Yagil C, Yagil Y, Luft F C
Franz Volhard Clinic, Berlin, Germany.
Hypertension. 1997 Jun;29(6):1252-9. doi: 10.1161/01.hyp.29.6.1252.
Salt-resistant (SBN/y) and salt-sensitive (SBH/y) Sabra rats are a useful model of salt-sensitive hypertension with incompletely explored renal mechanisms. We investigated their pressure-natriuresis curves, with and without deoxycorticosterone acetate (DOCA)-salt treatment. To differentiate between extrinsic neural and hormonal mechanisms and intrinsic renal influences, we performed experiments with neural denervation, adrenalectomy, and infusions of vasopressin, norepinephrine, 17-hydroxycorticosterone, and aldosterone as well as without these maneuvers. In untreated SBN/y without controlled neural and circulating hormonal factors, urine flow and sodium excretion increased from 32 to 95 microL/min per gram kidney weight (gkwt) and from 4 to 17 mumol/min per gkwt, respectively, as renal perfusion pressure was increased from 85 to 146 mm Hg. Renal blood flow and glomerular filtration rate were autoregulated and averaged 7.5 and 1.2 mL/min per gkwt. In untreated SBN/y with controlled neural and circulating factors, pressure-diuresis and -natriuresis curves were shifted toward the right, and renal blood flow and glomerular filtration rate ranged between 4.2 and 9.1 or 1 and 1.3 mL/min per gkwt as perfusion pressure was increased from 99 to 164 mm Hg. In both protocols, values in SBH/y did not differ. DOCA-salt increased blood pressure in SBH/y. In SBH/y without controlled neural and hormonal factors, pressure-diuresis and -natriuresis curves were shifted approximately 20 mm Hg toward the right. Fractional sodium and water excretion curves, renal blood flow, and glomerular filtration rate were shifted rightward in parallel. On the other hand, SBH/y with DOCA-salt and controlled neural and hormonal factors had lower sodium and water excretion rates only at the renal perfusion pressure of 150 mm Hg as well as decreased renal blood flow and glomerular filtration rate compared with DOCA-salt SBN/y. These data suggest that both extrinsic and intrinsic factors are responsible for reduced sodium and water excretory capacity in DOCA-salt SBH/y; however, the extrinsic factors may be more important.
耐盐（SBN/y）和盐敏感（SBH/y）的萨布拉大鼠是盐敏感性高血压的一种有用模型，其肾脏机制尚未完全阐明。我们研究了它们在有和没有醋酸脱氧皮质酮（DOCA）-盐处理情况下的压力-利钠曲线。为了区分外在神经和激素机制以及内在肾脏影响，我们进行了神经去支配、肾上腺切除术实验，并输注了血管加压素、去甲肾上腺素、17-羟皮质酮和醛固酮，也进行了未采取这些操作的实验。在未处理的、没有控制神经和循环激素因素的SBN/y大鼠中，随着肾灌注压力从85毫米汞柱增加到146毫米汞柱，尿流率和钠排泄量分别从每克肾脏重量（gkwt）32微升/分钟增加到95微升/分钟，以及从每克肾脏重量4微摩尔/分钟增加到17微摩尔/分钟。肾血流量和肾小球滤过率呈自身调节，平均分别为每克肾脏重量7.5毫升/分钟和1.2毫升/分钟。在有控制神经和循环因素的未处理SBN/y大鼠中，压力-利尿和压力-利钠曲线向右移动，随着灌注压力从99毫米汞柱增加到164毫米汞柱，肾血流量和肾小球滤过率分别在4.2至9.1毫升/分钟/克肾脏重量或1至1.3毫升/分钟/克肾脏重量之间。在这两种方案中，SBH/y大鼠的值没有差异。DOCA-盐使SBH/y大鼠的血压升高。在没有控制神经和激素因素的SBH/y大鼠中，压力-利尿和压力-利钠曲线向右移动约20毫米汞柱。钠和水排泄分数曲线、肾血流量和肾小球滤过率平行向右移动。另一方面，与DOCA-盐处理的SBN/y大鼠相比，有DOCA-盐且有控制神经和激素因素的SBH/y大鼠仅在肾灌注压力为百50毫米汞柱时钠和水排泄率较低，同时肾血流量和肾小球滤过率降低。这些数据表明，外在和内在因素均导致DOCA-盐处理的SBH/y大鼠钠和水排泄能力降低；然而，外在因素可能更重要。
