Preferential renal vasodilator effects of CGP 22979A in conscious spontaneously hypertensive rats

CGP 18137A (2-hydrazino-5-n-butyl-pyridine) and its prodrug CGP 22979A [N-acetyl-L-glutamic acid-N-[N2-(5-n-butyl-2-pyridyl)hydrazide]] were evaluated for their blood pressure-lowering potency and regional hemodynamic actions in conscious spontaneously hypertensive rats. The effects were compared to those of hydralazine. Animals were instrumented with miniaturized pulsed Doppler flowprobes to allow continuous simultaneous measurement of renal, mesenteric and hindquarter blood flow. From changes in mean arterial pressure and the respective flows, changes in renal, mesenteric and hindquarter resistance were calculated. After i.v. administration, hydralazine and CGP 18137A were equally potent with regard to their blood pressure-lowering effect in a dose range of 0.1 to 1 mg/kg. Hydralazine was more effective than CGP 18137A in lowering renal and hindquarter resistance. Neither of the two drugs, however, caused preferential dilation in any of the three beds studied. CGP 22979A in doses of 1 to 30 mg/kg caused a much smaller acute blood pressure-lowering response. However, already at low doses (1-10 mg/kg) it caused a significant reduction of renal resistance, without affecting either hindquarter or mesenteric resistance. At the highest dose (30 mg/kg), selectivity was no longer retained, which is probably due to excessive leakage of the active vasodilator into the peripheral circulation. These findings suggest that CGP 22979A is a renal-selective prodrug for CGP 18137A and thereby is capable of preferentially dilating the renal vasculature in conscious unrestrained spontaneously hypertensive rats.     

Effects of fenoldopam on regional vascular resistance in conscious spontaneously hypertensive rats

The effects of fenoldopam, a selective dopamine-1 agonist, on regional blood flow and vascular resistance were examined in conscious unrestrained spontaneously hypertensive rats (SHR). Rats were instrumented chronically with pulsed Doppler flow probes to allow measurement of renal, mesenteric and hindquarters blood flow. Maximal changes in mean arterial pressure, heart rate and regional blood flow were recorded after i.v. administration of fenoldopam (1-1000 micrograms/kg). Fenoldopam produced a dose-dependent reduction in arterial pressure and increased heart rate in the conscious SHR. Significant increases in mesenteric (maximal = 69 +/- 10%) and renal (maximal = 42 +/- 4%) blood flows were observed at all doses of fenoldopam. In the hindquarters, vascular resistance was increased after low doses of fenoldopam (1-30 micrograms/kg), but decreased with higher doses (100-1000 micrograms/kg). After ganglionic blockade, hindquarter vasodilation was observed with fenoldopam at low (10 micrograms/kg) and high (500 micrograms/kg) doses. Pretreatment with metoclopramide (20 mg/kg) or SCH 23390 (30 micrograms/kg), a new selective dopamine-1 antagonist, significantly attenuated the vasodilator responses to fenoldopam in all three vascular beds. Pretreatment with propranolol failed to alter the vascular effects of fenoldopam, but reduced the tachycardia markedly. This study indicates that fenoldopam decreased regional vascular resistance in the renal, mesenteric and hindquarters vascular beds of the conscious SHR with the mesenteric vascular bed demonstrating the greatest reactivity. The vasodilation induced by fenoldopam in these vascular beds appeared to be due to stimulation of vascular dopamine-1 receptors.     

Hypotensive and renal vasodilator effects of carbocyclic adenosine (aristeromycin) in anesthetized spontaneously hypertensive rats

Systemic arterial pressure and renal blood flow were measured in pentobarbital-anesthetized spontaneously hypertensive rats to assess the influence and mechanism of action of metabolically stable adenosine analogs on renal hemodynamics. (-)-Aristeromycin (carbocyclic adenosine; CA), a model carbocyclic nucleoside, was characterized with respect to adenosine receptor pharmacology by comparison to the effects elicited by the prototypic adenosine analogs 5'-N-ethylcarboxamide adenosine (NECA; an adenosine A1 and A2 receptor agonist) and N6-cyclohexyl adenosine (an adenosine A1 agonist). Intravenous bolus injections of CA and NECA caused dose-dependent hypotension and renal vasodilatation. Although CA and NECA were equally efficacious hypotensive agents, NECA was approximately 100-fold more potent than CA. CA was a more efficacious renal vasodilator than NECA. In contrast, at doses which had minimal effects on systemic arterial pressure, N6-cyclohexyl adenosine decreased renal blood flow. The hypotensive and renovascular effects of the adenosine analogs but not those of a control vasodilator, methacholine, were attenuated by i.v. administration of the xanthines aminophylline and 8-phenyltheophylline; thus, the effects of the nucleosides on renal blood flow in vivo appear to be attributable in part to activation of adenosine receptors. The profile of cardiovascular effects caused by CA suggests that this agent acts primarily as an adenosine A2 receptor agonist.     

Effects of central administration of morphine on renal function in conscious rats

Systemic administration of morphine in rats produces an anti-natriuretic effect that is at least partially dependent on renal nerves. The present studies were carried out in order to assess the renal response to central administration of morphine. Male Sprague-Dawley rats were surgically prepared with arterial, venous and bladder cannulas. In addition, a guide cannula was placed into the lateral ventrical and secured to the surface of the skull. Experiments were carried out at least 3 days after surgery. Renal clearance measurements were 30 min each. After a basal period, morphine sulfate (4 micrograms/4 microliters) or vehicle was injected into the lateral cerebral ventricle. Two clearance measurements were obtained, followed by central administration of naloxone HCl (4 micrograms/4 microliters) or vehicle and two more clearance periods. Morphine administration had no effect on blood pressure or heart rate but caused a sharp reduction in sodium excretion (3200 +/- 958 vs 970 +/- 158 nEq/100 g/min in period 5; P less than .05). This response was reversed by the addition of naloxone (3280 +/- 583 nEq/100 g/min in period 5; P less than .05). Furthermore, morphine had no effect on renal plasma flow and glomerular filtration rate. Naloxone increased the renal plasma flow and glomerular filtration rate in morphine-treated rats, whereas it had no effect in controls. It is concluded that central administration of morphine in conscious rats enhances renal tubular sodium reabsorption by an opiate receptor-dependent mechanism.     

Effect of potassium supplementation on blood pressure and vasodilator mechanisms in spontaneously hypertensive rats

1. Supplementation with 1% (w/v) KCl solution significantly attenuated the blood pressure rise with age normally observed in spontaneously hypertensive rats, resulting in a difference in blood pressure of 18 mmHg after 5 weeks. 2. Urinary 6-keto-prostaglandin F1 alpha (the stable hydrolysis product of prostacyclin) and kallikrein excretion were significantly elevated in rats receiving potassium. 3. No difference was observed in sodium excretion during the initial days of potassium supplementation; however, the potassium-supplemented animals excreted relatively more sodium over the 5 week period. 4. Plasma renin activity was significantly reduced in those animals receiving potassium after 5 weeks. 5. It is proposed that a combination of increased systemic and/or renal prostacyclin and kallikrein synthesis may, in combination with reduced renin activity, contribute to the attenuation of blood pressure in potassium-supplemented spontaneously hypertensive rats.     

Role of renal nerves in excretory responses to administration of kappa agonists in conscious spontaneously hypertensive rats

The present study examined whether the renal sympathetic nerves contribute to the renal excretory responses produced by kappa opioid receptor agonist administration in conscious spontaneously hypertensive rats (SHR). Intravenous infusion of the kappa opioid receptor agonists, ketocyclazocine (KC) and U-50488H, produced increases in urine flow rate. KC and U-50488H infusion also resulted in a marked and sustained antinatriuresis which was promptly reversed by low-dose naloxone (50 micrograms/kg i.v.), thus suggesting an opioid receptor-mediated action of both agonists. Although these kappa agonists did not produce changes in glomerular filtration rate or renal plasma flow, efferent renal sympathetic nerve activity increased with the same time course as the antinatriuretic response. To investigate whether the decrease in urinary sodium excretion was mediated via the increase in efferent renal sympathetic nerve activity, experiments were repeated in SHR with prior bilateral renal denervation. These studies demonstrated that similar renal excretory responses (diuresis and a naloxone reversible antiinatriuresis occurred during infusion of KC and U-50488H in renal denervated as were seen in intact SHR. These studies indicate that the renal excretory responses to the kappa opioid agonists KC and U-50488H are not mediated through changes in renal hemodynamics or via a pathway requiring intact renal innervation. Because an antinatriuretic response was observed in renal denervated SHR, this suggests that kappa opioid receptor agonists may influence the renal tubular reabsorption of sodium by additional naloxone-sensitive mechanisms independent of intact renal innervation.     

Effects of antihypertensive drugs on renal function and atrial natriuretic polypeptide in spontaneously hypertensive rats with renal ablation

To determine whether pharmacological control of blood pressure could affect the renal function and levels of atrial natriuretic polypeptide (ANP) in spontaneously hypertensive rats (SHR) with renal ablation, and to ascertain the benefits of antihypertensive drugs, we studied effects of oral administration of captopril (50 mg/kg/day), an inhibitor of angiotensin converting enzyme, benidipine (3 mg/kg/day) and nilvadipine (10 mg/kg/day), newly developed blockers of calcium channel, and indapamide (10 mg/kg/day) for 14 days on systolic blood pressure, serum creatinine, blood urea nitrogen, and plasma ANP concentration in SHR subjected to surgical removal of the left kidney and infarction of two-thirds of the right kidney (5/6 nephrectomy) a week before. Three weeks after the surgery, systolic blood pressure (mmHg) in the untreated group was 253 +/- 9 (n = 10), in the captopril group 156 +/- 9 (n = 7, p less than 0.05), in the benidipine group 197 +/- 9 (n = 7, p less than 0.05), in the nilvadipine group 146 +/- 9 (n = 7, p less than 0.05) and in the indapamide group 206 +/- 5 (n = 7, p less than 0.05). Serum creatinine (mg/100 ml) was lower in the captopril group (0.58 +/- 0.02, n = 7, p less than 0.05) and in the benidipine group (0.50 +/- 0.03, n = 7, p less than 0.05) but not in the nilvadipine group and in the indapamide group 3 weeks after 5/6 nephrectomy compared to the untreated group. Blood urea nitrogen was also lower in the captopril group and in the benidipine group but not in the nilvadipine group and in the indapamide group. Plasma ANP concentration was significantly reduced by the treatment with captopril and benidipine but not with nilvadipine and indapamide. These results suggest that the reduction of blood pressure by the inhibition of angiotensin converting enzyme with captopril has the potential to ameliorate renal function of the SHR with remnant kidney, a model of chronic renal failure with hypertension, associated with the decreased concentration of plasma ANP. However, it remains to be determined whether the reduction of blood pressure by calcium channel blockers may be involved in the delayed progression of renal failure in this model since there were disparate effects on renal function and plasma ANP concentration with these two calcium channel blockers.     

Effects of saponins from Herniaria glabra on blood pressure and renal function in spontaneously hypertensive rats

Experiments were performed on male and female spontaneously hypertensive rats weighing 310-340 g (10 animals per group). The oral administration of 200 mg/kg/day of saponins from Herniaria glabra for 30 days, resulted in a significant decrease in blood pressure in hypertensive rats. The systolic and diastolic blood pressure decreased significantly and respectively from 187.60 +/- 20.63/119.00 +/- 7.09 mmHg at day 0 (D0) to 141.60 +/- 7.51/90.40 +/- 7.68 mmHg at day 30 (D30), p < 0.001 (vs. 186.30 +/- 11.27/114.10 +/- 12.00 mm Hg at D0 to 154.50 +/- 6.38/132.3 +/- 7.68 mmHg at D30 in furosemide-treated group, p < 0.001). Control animals receiving placebo did not show any significant variation in the mean arterial pressure. The effect of saponins of Herniaria glabra on renal function was evaluated in spontaneously hypertensive rats using clearance techniques. Glomerular filtration rate was constant in the control rats and increased significantly in the hypertensive rats after saponins treatment (5.55 +/- 0.32 vs. 6.03 +/- 0.43 ml.min-1.kg-1 in the control (C) and saponins (S) groups, respectively, p < 0.05). Saponins administration provoked an increase in urinary flow (59.38 +/- 5.85 ml.kg-1.24 h-1 vs. 36.92 +/- 5.17 ml.kg-1.24 h-1, p < 0.001). Saponins also increased potassium excretion (6.89 +/- 0.81 mmol.kg-1.24 h-1 vs. 5.40 +/- 0.51 mmol.kg-1.24 h-1, p < 0.001) and sodium excretion (10.74 +/- 1.21 mmol.kg-1.24 h-1 vs. 7.25 +/- 0.54 mmol.kg-1.24 h-1, p < 0.001) as well as chloride excretion (13.59 +/- 1.04 mmol. kg-1.24 h-1 vs. 9.67 +/- 0.77 mmol.kg-1.24 h-1, p < 0.001). It is concluded that chronic oral administration of saponins from Herniaria glabra decreased the arterial blood pressure and affected salt and water transport in renal tubules.     

复方鳖甲软肝方对自发性高血压大鼠心肌纤维化的抑制作用

目的:评价复方鳖甲软肝方对自发性高血压大鼠(SHR)心肌纤维化、左室重构及血浆中血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)、醛固酮的效应。方法:实验选用12周龄SHR50只,随机将其分为5组,即空白对照组、依那普利组、小、中、小剂量复方鳖甲组(小、中、大剂量药物组),每组各10只。另取正常SD大鼠10只作为正常对照组。测定治疗10周后各组大鼠收缩压、心脏质量指数(heartweightindex,HWI)、左室质量指数(leftventricularmassindex,LVMI)、胶原蛋白含量,血浆中血管紧张素Ⅱ、醛固酮含量,心肌胶原容积分数(collagenvolumefraction,CVF)和血管周围胶原面积(perivascularcircuferentialarea,PVCA)。结果:治疗10周后,空白对照组大鼠收缩压,HWI,LVMI,胶原蛋白含量犤(195±9)mmHg,(5.38±0.25),(3.81±0.09),(6.13±0.93)mg/g,1mmHg=0.133kPa犦均明显高于正常对照组犤(127±10)mmHg,(3.88±0.28),(2.57±0.17),(4.19±0.72)mg/g犦(P<0.01)。依那普利组大鼠收缩压明显低于与空白对照组(P<0.01),而复方鳖甲软肝方各组收缩压比较,差异无显著性意义(P>0.05);依那普利组大鼠HWI,LVMI明显低于空白对照组(P<0.01),而复方鳖甲软肝方各组差异无显著性意义(P>0.05);依那普利组,复方鳖甲软肝方中、大剂量组大鼠心肌组织胶原蛋白含量     

运动训练及依那普利对自发性高血压慢性肾功能衰竭大鼠模型肾功能的影响

目的:应用高血压肾功能衰竭大鼠模型,探讨运动训练与肾素血管紧张素转换酶抑制剂依那普利联合应用对肾功能的影响。方法:8周龄雄性自发性高血压大鼠24只,行右肾2/3切除,左肾全摘除,建立5/6肾切除自发性高血压慢性肾功能衰竭模型。于10周龄时,随机分为非运动组、中等强度运动训练组和运动训练加依那普利组。其中运动训练组所有动物进行跑台训练,速度20m/min,60min/d,5d/w。依那普利2mg/(kg·d)腹腔内持续给药。结果:4周运动训练明显抑制尿蛋白分泌,减小肾小球硬化指数。而运动训练加依那普利使血压明显下降和进一步减小肾小球硬化指数。结论:中等强度运动训练对慢性高血压肾功能衰竭模型有延缓肾衰进展、保护肾功能的作用。运动训练与依那普利联合应用能进一步增强这种肾脏保护作用。     

运动对高血压大鼠血压和内皮素的影响

目的押观察原发性高血压大鼠运动后血压、体质量以及血清内皮素的变化。方法押实验于2003-07/09在扬州大学实验动物中心完成。采用18只高血压大鼠作为实验动物,按实验需要将动物分为运动组穴10只雪和安静组穴8只雪。运动组经过10周的60min/d的训练熏5d/周,与安静组一起测量其血压、体质量;取静脉血,用放射免疫法测定内皮素。结果押实验进行至第5周运动组死亡1只大鼠。①血压:运动前两组大鼠血压无显著差异熏经过4,10周运动后运动组大鼠与安静组相比血压明显降低眼(174.1±1.4),(185.0±1.4)mmHg;(166.6±1.1),(193.9±1.8)mmHg,P<0.01演。②体质量:两组动物在生长过程中体质量均逐渐增高,但运动组增长的趋势低于安静组,经10周运动后运动组的体质量明显低于安静组眼(344.60±2.57),(362.00±5.26)g,P<0.05演。③内皮素:经过10周的游泳训练后,运动组内皮素明显低于安静组眼穴44.75±4.45雪,穴68.36±5.93雪ng/L,P<0.01演。结论押运动对高血压大鼠的体质量增长有抑制作用,且高血压大鼠经过游泳训练后其血内皮素水平下降,而血压也随之下降,提示运动对高血压大鼠的降压部分是通过影响内皮素的产生和释放来实现的。     

低强度游泳运动对自发性高血压大鼠C反应蛋白的影响

目的研究低强度游泳运动对自发性高血压大鼠(SHR)C反应蛋白(CRP)的影响。方法24只8周龄SHR大鼠随机分为对照组及运动组,运动组进行游泳运动1 h/d,5 d/w,共10 w。每周测量大鼠尾动脉压,实验结束时检测CRP水平。结果10 w低强度游泳运动明显降低SHR大鼠血压及CRP水平。结论低强度游泳运动有助于降低高血压患者的血压并减少心血管系统并发症。     

肝细胞生长因子对自发性高血压大鼠血压的影响

背景：肝细胞生长因子是一种多功能生长因子，它能促进多种细胞生长与移行及各种组织器官的发生。在心血管系统，它具有抗凋亡、抗纤维化、促进内皮细胞损伤后修复作用，推测其可能具有降压效应。 目的：观察外源性肝细胞生长因子对自发性高血压大鼠血压、血管内皮系统和肾素-血管紧张素系统的影响并探讨其调节血压的可能机制。设计、时间及地点：随机对照动物实验，于2007—03／07在安徽医科大学第一附属医院心内科完成。材料：外源性肝细胞生长因子粉剂购于美国Peprotech公司，成年白发性高血压大鼠组和WKY大鼠，均14周龄，体质量200～250g。自发性高血压大鼠随机分为实验组和单纯自发性高血压大鼠组，WKY大鼠为正常对照组，每组12只。方法：实验组每间隔24h从尾静脉依次给予肝细胞生长因子5，10，15，20，25u玳g，自发性高血压大鼠组和正常对照组同时给予等量生理盐水。每次注射安抚大鼠5min后测血压与心率，最后一次注射后观察血压降至最低值时（约注射后30min），麻醉后处死，各取右心室血2mL。 主要观察指标：①观察肝细胞生长因子对自发性高血压大鼠组收缩压及心率的影响。②分别用比色法测血清一氧化氮水平、放射免疫法测血浆内皮素、血管紧张素Ⅱ水平。 结果：实验组注射肝细胞生长因子5μg/g血压下降不明显，注射10ug／kg约5min后血压开始下降，30min降至最低，1h后血压开始逐渐回升，5h后血压基本回到原先水平。注射20ug／kg达最大降压幅度，收缩压下降达40～50mmHg，再增加剂量最大降压幅度及持续时间不变。整过程心率无明显变化。两个对照组血压无明显变化。实验组较自发性高血压大鼠组内皮素、血管紧张素Ⅱ含量下降，一氧化氮含量上升（P〈0．05）。 结论：从静脉给予外源性肝细胞生长因子能快速降低自发性高血压大鼠组的血压，在一定剂量范围内，呈剂量-效应与时间-效应关系。肝细胞生长因子系统、血管内皮系统、肾素-血管紧张素系统可能共同参与血压的调节。     

Evaluation of a novel antihypertensive agent, LY127210, in anesthetized and conscious spontaneously hypertensive rats

LY127210 (7,8-dimethoxy-1H-3-benzazepin-2-amine, hydrochloride) is a novel peripheral arterial vasodilator that reduces mean arterial blood pressure in anesthetized and conscious spontaneously hypertensive rats by all conventional routes of administration. The antihypertensive activity of LY127210 results predominantly from a decrease in total peripheral vascular resistance, and the degree of reflex tachycardia produced by LY127210 in conscious spontaneously hypertensive rats is significantly less than that produced by hydralazine at equivalent antihypertensive doses. The relative lack of reflex tachycardia produced by LY127210 appears to result from a direct bradycardic effect of the compound that occurs at the level of the myocardium at doses similar to those required to produce peripheral arteriolar vasodilation. It is proposed that the direct bradycardic effect of LY127210 serves to offset, at least in part, the tachycardia resulting from reflex stimulation of sympathetic outflow that occurs upon activation of the baroreflex loop as blood pressure is lowered. The results indicate that LY127210 may provide adequate control of blood pressure and may not require the concomitant administration of a beta-adrenoceptor antagonist to control reflex tachycardia, as is commonly necessary with hydralazine.     

Regional hemodynamic effects of rilmenidine and clonidine in the conscious spontaneously hypertensive rat

Rilmenidine is an oxazoline analogue that has antihypertensive properties that resemble those of clonidine. Since rilmenidine has recently been described to have a relatively greater affinity for imidazoline receptors than clonidine, it was of interest to study whether this has functional consequences with regard to the regional hemodynamic responses. We investigated regional hemodynamics in conscious spontaneously hypertensive rats, equipped with miniature Doppler flow probes on the renal and mesenteric arteries and on the abdominal aorta. Clonidine (3-30 micrograms/kg) and rilmenidine (0.2-3 mg/kg) induced similar, dose-dependent reductions in heart rate. Both also induced an early hypertensive response, which was greater with rilmenidine, and similar later blood pressure reductions, which were maintained over 3 h. The early hypertensive response was associated with generalized vasoconstriction. Rilmenidine caused slightly greater mesenteric and hindquarter constriction than clonidine, whereas renal effects did not differ significantly. During the hypotensive phase, rilmenidine was a less potent mesenteric and hindquarter vasodilator than clonidine. During this phase, renal blood flow was at control levels, probably indicating autoregulation of renal flow. The minor differences in regional hemodynamic effects suggest that clonidine and rilmenidine can both be used as potent antihypertensives. The fact that rilmenidine has been suggested to possess less sedative side-effects suggests that, on this basis, it may be superior for antihypertensive drug therapy.     

Effects of morphine on the renal handling of sodium and lithium in conscious rats

The present study was carried out in order to assess the renal response to i.v. morphine in the rat, particularly the effects on tubular handling of sodium and lithium. Rats were prepared surgically with arterial and venous catheters and bladder cannulas. Clearance experiments and measurements of blood pressure and heart rate were carried out at least 4 days after surgery in unanesthetized animals. Intravenous administration of morphine (4 mg/kg b.wt.) caused a decrease in fractional sodium excretion, (at 90 min after injection, vehicle, 2.49 +/- 0.30% vs. morphine, 1.12 +/- 0.17%, P less than .05), in the absence of significant changes in systemic hemodynamics or glomerular filtration rate. This effect was prevented by pretreatment with naloxone. Enhanced proximal tubular reabsorption of sodium was considered as a possible explanation for the decrease in sodium excretion which followed morphine administration. Proximal tubular fluid reabsorption was estimated utilizing the lithium clearance method. Results indicated a reduction in fractional excretion of lithium by morphine administration (at 90 min, vehicle, 34.2 +/- 3.3% vs. morphine, 18.8 +/- 2.3%, P less than .05), which was also prevented by naloxone pretreatment. It is concluded that, under the present experimental conditions, morphine enhances tubular reabsorption of sodium by an opiate receptor-dependent mechanism and that this effect is, at least in part, localized in the proximal tubule.     

Effects of diuretics on stroke development in Kyoto-Wistar stroke-prone spontaneously hypertensive rats.

1. Previous studies have indicated that increases in dietary K+ promote diuresis and retard stroke development in stroke-prone spontaneously hypertensive rats (spSHR) fed a Japanese-style diet containing 4% NaCl. 2. It is possible that elevations in dietary K+ retard stroke development by inducing natriuresis and facilitating the clearance of Na+, and that diuretics associated with natriuresis might also be capable of retarding stroke development in spSHR. To test if this was the case, the onset of stroke development in spSHR fed a low (0.75%) K+ diet containing 4% NaCl (controls) was monitored and compared with that in spSHR treated with (a) frusemide, (b) chlorothiazide, (c) amiloride or (d) acetazolamide, and with (e) untreated spSHR fed a high (2.11%) K+ diet. 3. The onset of stroke, as well as death resulting from stroke, occurred at a significantly later age in spSHR fed a high K+ diet than in spSHR fed a low-K+ diet, despite the fact that both groups of spSHR rats had comparable blood pressures. 4. Treatment of spSHR with the above-named diuretics before stroke development did not alter the blood pressure of the rats. The onset of stroke development and death in spSHR treated with chlorothiazide, amiloride or acetazolamide was comparable with that observed in untreated control spSHR. In spSHR treated with frusemide, the onset of stroke was comparable with that of untreated control spSHR, whereas the onset of death after stroke development was accelerated. 5. Post mortems performed on spSHR that developed stroke indicated the presence of haemorrhagic stroke of comparable severity in the six groups of spSHR studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

丹参酮ⅡA对自发性高血压大鼠心肌醛固酮合成相关基因表达的影响

目的　探讨丹参酮ⅡA对心肌醛固酮合成相关基因表达的作用。方法　雄性自发性高血压大鼠 (SHR) 2 0只 ,分为两组 :高血压组、丹参酮ⅡA组 ,分别腹腔注射生理盐水、丹参酮ⅡA12周。通过逆转录 聚合酶链反应 ,以GAPDH为内参照 ,测定两组心肌CYP11B1、CYP11B2的mRNA表达量。结果　丹参酮ⅡA组CYP11B1及CYP11B2的mRNA表达水平明显低于高血压组 (0 92 4± 0 12 1vs 1 343± 0 132 ,P <0 0 5 ;1 0 17± 0 119vs 1 6 75± 0 12 6 ,P <0 0 1) ,GAPDH的mRNA水平在两组间无显著差异 (P >0 0 5 )。结论　丹参酮ⅡA治疗可抑制心脏醛固酮合成相关基因CYP11B1及CYP11B2的mRNA表达     

肝细胞生长因子联合缬沙坦对自发性高血压大鼠心肌细胞凋亡的影响

目的观察肝细胞生长因子(HGF)联合缬沙坦对自发性高血压大鼠(SHR)心肌凋亡的影响。方法 24只14周龄雄性SHR随机分为4组(n=24):阳性对照组(P组,常规饲养,无药物干预)、HGF组(H组,开胸,左心室壁五点直接注射5×109Pfu/mL Ad5-HGF,0.1 mL,术后常规饲养4周),缬沙坦组(V组,缬沙坦灌胃30 mg·kg-1·d-1,4周),HGF联合缬沙坦组(HV组,开胸,左心室壁五点直接注射5×109Pfu/mL Ad5-HGF,0.1 mL,术后缬沙坦灌胃30 mg·kg-1·d-1,4周),雄性Wistar大鼠(WKY)为健康对照(N组,n=6)。治疗前及治疗后每周测量一次尾动脉压。4周后处死大鼠,TUNEL法测心肌凋亡指数,ELASA法测心肌HGF、caspase-3浓度,免疫组织化学法及图像分析系统分析心肌Bcl-xl水平。结果治疗4周后,HV组、V组血压较P组、H组明显下降(P0.05);与P组相比,H组、V组、HV组心肌凋亡指数及心肌caspase-3浓度明显降低(P0.05),心肌HGF、抗心肌凋亡蛋白Bcl-xl水平明显升高(P0.05),且联合用药组尤为显著。结论HGF、缬沙坦均可有效抑制SHR左心室心肌细胞凋亡,改善心室重构,且联合使用效果优于HGF、缬沙坦的单独应用。