Capillary Permeability to Albumin in Normotensive and Spontaneously Hypertensive Rats

Transcapillary passage of plasma proteins is enhanced in man's primary hypertension and it is debated whether this reflects increased permeability or merely a raised capillary pressure. To elucidate this problem, maximally vasodilated hindquarters of spontaneously hypertensive rats (SHR) and normotensive controls (NCR) were perfused in parallel at constant flow with dextran, horse serum or mixtures of the two, using labelled albumin as indicator of capillary permeability to macromolecules. By equal increases of venous pressure modest filtration was maintained during one hour, after which the edema and its albumin content were determined. — There was less edema in SHR, reflecting a slightly lower postcapillary resistance and a much higher precapillary resistance compared with NCR, which here resulted in a lower capillary pressure in SHR. In both SHR and NCR the presence of dextran slightly enhanced the capillary filtration coefficient but increased albumin permeability up to tenfold, also after antihistamine drugs. However, for each perfusate the SHR capillaries were, if anything, slightly less permeable to albumin than the NCR ones. — The results suggest that the enhanced transcapillary passage of plasma proteins in primary hypertension reflects an increased capillary pressure in some circuit(s), probably mainly skeletal muscle, resulting from the functional balance in vivo between the pre- and postcapillary resistances.     

Combined Effects of Hypokinesia and Ambient Temperature on Heart Remodeling in Normotensive and Hypertensive Rats

Bulletin of Experimental Biology and Medicine - We studied the effect of hypokinesia combined with cold exposure on morphological parameters of the heart in Wistar-Kyoto rats and rats with...     

Development of Hypertensive Status in NISAG Rats Reared by Normotensive Wistar Rats

Parameters of the cardiovascular system and the content of corticosterone, thyrotrophin, thyroxin, and triiodothyronine in the plasma, and norepinephrine in the myocardium were determined in male NISAG rats (hereditary stress-induced arterial hypertension) reared by normotensive Wistar rats. Cross-rearing of hypertensive rat pups by normotensive females attenuated arterial hypertension with a tendency to normalization of the examined parameters. This confirms the possibility of modifying hypertensive phenotype by changing the conditions of the early postnatal development.     

Comparison of the Somatosympathetic Reflex in Normotensive and Spontaneously Hypertensive Rats

Acute experiments under chloralose anaesthesia were performed in normotensive (Wistar and Wistar-Kyoto) and hypertensive (SHR) rats for recording of electrical discharge in the upper cervical sympathetic stem in response to stimulation of afferent fibers of the median nerve of the forelimb. These experiments showed that the evoked response was of the same shape in hypertensive rats as in normotensive rats. The latent period, duration of each discharge, and spectral characteristics of the somatosympathetic reflex were identical in animals of all the lines studied, though the amplitude of the reflex was greater in SHR rats than in normotensive animals. It is suggested that the organization of the somatosympathetic reflex is identical in hypertensive and normotensive rats. The reflex excitability of the sympathetic nervous system was increased in SHR rats.     

Nitroxidergic Neurons in Nuclei of the Medulla Oblongata in Hypertensive and Normotensive Rats

Photoprotective activity of heteroaromatic compounds (derivatives of 3-hydroxypyridine, amino-6-hydroxybenzothiazole, and 5-hydroxybenzimidazole) was studied in the system of UV-induced cardiolipin peroxidation. Although all three compounds had the antioxidant effect during free radical oxidation of luminol, only derivatives of amino-6-hydroxybenzothiazole and 5-hydroxybenzimidazole inhibited the process of UV-induced lipid peroxidation. The 3-hydroxypyridine derivative did not inhibit UV-induced cardiolipin peroxidation, which was probably related to degradation of this compound under the influence of UV light and formation of degradation products that cannot inhibit free radical processes. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 2, pp. 152-154, February, 2009     

The Distribution of Sodium in Aortic Walls from Spontaneously Hypertensive and Normotensive Rats

The contents of exchangeable sodium, bound sodium and total water and the extracellular space of thoracic aortas from normotensive and spontaneously hypertensive rats were measured. The aortas from the hypertensive rats contained more sodium than those from the normotensive animals while the total water content and extracellular space in the two groups were the same. The capacity to bind sodium in an osmotically inactive form was greater in the aortas from the hypertensives than in those from the normotensives. The difference in binding capacity was of the same order of magnitude as the difference in sodium content, indicating that the excess sodium in the thoracic aortas from the hypertensive rats was osmotically inactive and thus unable to cause water logging.     

Arthritis Induced by Adjuvant in Spontaneously Hypertensive and Normotensive Rats: Endogenous Glucocorticoid Effects on Inflammatory Response

The present study investigated arthritis induced by complete Freund adjuvant (AIA) in spontaneously hypertensive and normotensive rats (respectively, SHR and NTR rats). The inflammatory reaction was studied for 28 days by evaluating paw edema and secondary lesions found 10 days after complete Freund adjuvant (CFA) administration. The body weight of the animals and macroscopic alterations of several organs, including spleen, thymus, adrenal glands, and lymph nodes, were also analyzed. The results showed that the AIA manifestations were decreased in SHRs compared with NTRs. Moreover, this altered inflammatory response was not modified by surgical adrenalectomy.     

Acute Immune and Non-Immune Inflammatory Response in Spontaneously Hypertensive Rats and Normotensive Rats. Role of Endogenous Nitric Oxide

Summary The present study investigated the acute inflammatory response (increase in vascular permeability and leukocytes migration) in the pleura of spontaneously hypertensive rats (SHR) and normotensive rats (NTR), using two different stimulus: carrageenan and active anaphylaxis. In addition, the role of endogenous nitric oxide in these responses was investigated. Results The inflammatory response induced by intrapleural carrageenan injection in SHR developed similarly to that in NTR. Treatment with L-NAME, reduced the intensity of this response in both groups of rats. The inflammatory response induced by active anaphylaxis in SHR and NTR was different. The increase in vascular permeability occurred later in the SHR compared to NTR. The number of leukocyte present in inflammatory exudates was increased at 4 h in both groups of rats. L-NAME treatment did not inhibit exudation at the intervals under analysis, however, reduced the number of mononuclear cells in the inflammatory exudate of SHR. Conclusion The development of the inflammatory response in SHR differs from that in NTR, depending on the nature of the inflammatory stimulus. Endogenous NO plays a clear role in carrageenan-induced inflamma-tion, but not in immunologically mediated inflammation in the analyzed period.     

Effect of Angiotensin-Converting Enzyme Inhibitor Quadropril on Dynamic Parameters of Vascular Tone under Conditions of NO Synthesis Blockade in Normotensive and Spontaneously Hypertensive Rats

The role of NO in the mechanism of quadropril modulation of the flow-dependent vasodilation was examined in normotensive (Wistar) and spontaneously hypertensive (SHR) rats. The abdominal aorta was cannulated and autoperfused at different volume rates to obtain the pressure-flow curves. In the first experimental series, the blood flow-pressure dependence was measured before and after intravenous injection of quadropril (1 mg/kg). In the next series, this dependence was obtained before and after injection of NO-synthase inhibitor L-NNA (10 mg/kg) and quadropril, respectively. Quadropril potentiated vasodilation caused by an increase in perfusion volume rate in both normo- and hypertensive rats and stabilized intravascular pressure. Inhibition of NO synthesis elevated hydraulic resistance and decreased stability of intravascular pressure in normo- and hypertensive rats. In normotensive rats, these changes were promoted by a decrease in vascular distensibility. Under these conditions, quadropril pronouncedly potentiated the flow-dependent vasodilation only in SHR rats, which was revealed methodically by an increase in perfusion rate in the posterior quarter of the body. Thus, in SHR rats the quadropril-potentiated vasodilation in response to increased perfusion rate does not depend on NO synthesis.     

Vasculosyncytial Membrane in Placental Villi of Normotensive and Hypertensive Pregnancies

Vasculosyncytial membranes appear as thin blister like protrusion on the villous surface and form the only physical barrier between fetal and maternal blood. Paucity of vasculosyncytial membrane leads to fetal hypoxia and appears to subject the fetus to considerable risk.This study was conducted to see the incidence of vasculosyncytial membrane in placental villi of normotensive and hypertensive pregnancies.A total of 40 patients were selected from Obstetrics and Gynaecology Department, J.N.M.C.H., A.M.U., Aligarh and they were categorized into normotensive and hypertensive groups having 20 cases in each group respectively. Most of cases in normotensive group were multigravidae and aged between 25 to 35 yrs while cases in hypertensive group were above 35 yrs of age and mostly nulliparous. Placentas of each group were fixed in 10% formalin solution and processed for section cutting. 5μ thick sections were prepared and stained with haematoxylin & eosin and observed under light microscope.A total of 200 villi per high power field (hpf)were counted in each slide and obtained data were expressed as mean ± standard deviation. It was found that there was complete absence of vasculosyncytial membrane in placental villi of hypertensive patients.     

Cardiac and Metabolic Activity in Mild Hypertensive and Normotensive Subjects

Heart rate, respiration, and metabolic activity were monitored at rest and during the mental challenge of a video game in 22 mild hypertensive and 53 normotensive young men. Subjects also completed the Eysenck Personality Questionnaire and the Jenkins Activity Survey. The mild hypertensive subjects displayed higher resting heart rates than the normotensives and larger magnitude heart rate increases to the video game. Although groups did not differ in resting respiratory activity, the metabolic rates tended to be higher in the mild hypertensives and they showed reliably greater increases in oxygen consumption and carbon dioxide production during mental challenge. These data were subjected to a variety of interpretations. However, in the absence of psychophysiological assessment during physical exertion, and without direct measurement of cardiao output and arteriovenous oxygen differences, the present results did not permit a choice to be made between rival explanations, and they certainly cannot discount the hypothesis that some borderline hypertensives display excessive cardiac activity and tissue overperfusion during stress. The personality measures did not differentiate groups. However, correlational analyses within each group revealed that whereas systolic blood pressure was positively and significantly related to neuroticism in the mild hypertensive group, for the normotensive subjects the direction of correlation was reversed. In addition, scores on the Jenkins Activity Survey correlated positively with heart rate reactivity to the video game for the mild hypertensives, but not for the normotensives.     

自发性高血压大鼠的微血管改变及其与血管内皮细胞损伤的关系

目的：探讨自发性高血压大鼠（SHR）的微血管改变与血管内皮细胞（VEC）损伤的关系。方法：以10只成年Wistar－Kyoto大鼠（WKY）为正常对照组（WKY组）。观察、计数10只成年SHR的肠壁微动脉管径和分支数，同时测定血浆亚硝酸根（NO2－）和内皮素（ET）并与WKY组对照。结果：SHR组的肠壁各级微动脉管径较WKY组变细（P＜0．01～0．001）、各级微动脉总条数较WKY组减少（P＜0．001～0．0001）；SHR组的血浆NO2-水平和K值［10g（NO2－／ET）」较WKY组低（P＜0．05～0．001），而ET较WKY组高（P＜0．05）。血压和K值分别与肠壁微动脉管径和条数呈负相关和正相关（P＜0．005～0．001）。结论：高血压的微血管结构异常与VEC损伤有密切的关系。     

开博通与左旋精氨酸对自发性高血压大鼠血管内皮细胞功能的影响

观察开博通(CPT)和左旋精氨酸(L-Arg)对自发性高血压大鼠(SHR)血管内皮细胞功能影响 ,探索两者联合使用的降压机制。方法Wastar大鼠10只作正常对照组。另38只SHR随机分为SHR对照组(n=10),L_Arg治疗组(n=10),CPT治疗组(n=9),L_Arg和CPT联合治疗组(n=9)。同时测各组用药前后的血压 ,一氧化氮(NO)和内皮素(ET)。结果SHR组的NO低于正常对照组而ET则高于对照组(P<0.05) ,L_Arg和/或CPT两治疗组的NO和ET各有不同程度升高和降低 ,(与SHR组比较均P<0.05) ,其中以L—Arg CPT联合治疗组最明显。3个治疗组用药后血压较用药前均有不同程度的下降(均P<0.001) ,而又以L—Arg CPT联合组降压效果最佳。结论CPT和L_Arg均可有效增加SHR的NO合成释放 ,加强CPT降压效应     

卡托普利对自发性高血压大鼠微血管稀少和内皮功能障碍的影响

为探讨自发性高血压大鼠（SHR）的微血管改变和血管内皮细胞（VEC）功能障碍的关系及卡托普利（CPT）的干预效果，对9只SHR给予CPT（CPT组），并以10只WKY大鼠作为正常对照组（WKY组），以10只SHR作为实验纠（SHR组），观察检测人鼠的血压（BP）、回肠壁各级微动脉分支总数、血浆一氧化氮（NO）和血浆内皮素（ET）。结果显示，SHR组的微动脉分支总数、NO及K值[log(NO／ET)]均较WKY组下降（P均<0.01），而ET则增高（P＜0．01）；CPT组给药后第7口BP较给药前下降（P<0．01），其微动脉分支总数、NO及K值均较SHR组增加（P均<0．01）；SHR的BP与K值呈负相关（r=－0．5863），BP与各级微动脉分支总数呈负相关(r＝－0．7866～－0．6380），而K值与各级微动脉分支总数呈正相关（r＝0.5951～0.7529）。认为SHR的微血管改变与其内皮功能状态关系密切，CPT时改善高血压的VEC功能和微血管稀少现象，从而发挥降压作用。     

A Harmonic Analysis of Cardiac Response of Normotensive and Hypertensive Adolescents during Stress

Abstract

In this paper, a statistical analysis is applied to the systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR) data of 23 normotensive (NT) and 24 hypertensive (HT) adolescents who underwent a 10-minute mental stress regimen. Readings were measured at one-minute intervals. The harmonic time series analysis is based on the data of an eight-minute interval of the stress phase. The NT group established a statistically significant (p <.05) rhythmic variation described by a sinusoidal wave about a near pre-stress mean. The HT group exhibits for the three parameters a near constant response about a significantly elevated level. The consistent existence of a rhythmic pattern for the NT subjects under mental stress, in contrast to the constant response for the HT subjects, suggests that mental stress causes a change in the “natural” rhythmic pattern of cardiac response for the HT subject alone.     

Mechanisms of Modulation of Thermoregulatory Reactions during Cooling in Hypertensive Rats by the Sympathetic Nervous System

Susceptibility of thermoregulatory responses to cold to blockage of α₁- and β-adrenoreceptors differs in health and hypertension. α₁-Adrenoceptor blockade reduces vessel reactivity during cooling and vessel reaction to cold becomes similar to that in intact normotensive rats. Changes in the structure of metabolic response to cold in favor of non-shivering thermogenesis typical of hypertensive animals becomes even more pronounced under conditions of α₁-adrenoceptor blockade due to inhibition of cold shivering. Blockage of β-adrenoceptors does not affect parameters of vascular response to cooling. In hypertensive rats, in contrast to normotensive animals, β-adrenoceptor blockade during cooling increased temperature thresholds for total metabolic reaction and shivering. The maximum shivering intensity also increased, which partially compensated inhibition of non-shivering thermogenesis. In the whole organism, blockade of one type of adrenoceptors during cooling leads to intensification of compensatory mechanisms realized through adrenoceptors of the other type. In hypertensive rats, compensatory capacities of thermogenic processes controlled by α₁- and β-adrenoceptors are impaired in comparison with normotensive animals under conditions of inhibition of both shivering and non-shivering thermogenesis.     

国产血管生成素对微血管稀少及血管内皮细胞作用

本研究旨在研究国产血管生成素对微血管稀少和血管内皮细胞的作用。观察对象为WKY鼠5周龄组、8周龄组、13周龄组和血管生成素治疗组。观察指标为微动脉A2、A3和A4。研究结果提示血管生成素可以预防微血管稀少并延缓靶器官细胞损害。     

SHR大鼠冲动性变化的初步观察

目的 :探究注意缺陷多动障碍 (AD HD)动物模型 (自发高血压大鼠 ,SHR)冲动性的变化。方法 :实验在标准Campden连续反应测试箱中进行 ,大鼠禁水 2 2h ,采用长变异间期方案 (长VI,40天 ,变异指数为 180s) ,分析最后 10天稳定曲线的均值。结果 :1、SHR及对照WistarKyoto (WKY)组大鼠按杠获水次数无显著差异。 2、按杠短反应间期 (IRT) :( 1)SHR组的IRT 0 0 ( 0 0 0～ 0 33s)和IRT 0 1( 0 33～ 0 6 6s)均非常明显地高于WKY组 (P <0 0 1)。 ( 2 )整个实验过程的三个相同阶段两组大鼠的短IRT之间均无明显差异。结论 :本实验结果说明SHR大鼠的冲动性要较WKY大鼠强 ,这有助于解释ADHD的发病机理及临床的治疗。