Mozek a ledviny hrají klíčovou úlohu v patogenezi hypertenze. Sympatický nervový systém (SNS) je hlavním efektorem mozkové regulace cévního tonu a je také odpovědný za abnormální funkci ledvin u sůl-sensitivní hypertenze (ß2-WNK4-NCC dráha). Naopak, renin-angiotensinový systém (RAS) je hlavním regulátorem funkce ledvin u sůl-resistentní hypertenze. RAS také moduluje sympatickou vasokonstrikci svými centrálními i periferními účinky. Cílem tohoto projektu je zhodnotit úlohu těchto systémů (se zvláštním zřetelem k ß2-WNK4-NCC dráze) při vývoji různých forem experimentální hypertenze podobajících se lidské sůl-sensitivní a sůl-resistentní hypertenzi. Rozdíly v úloze SNS a RAS při kontrole krevního tlaku, funkce ledvin a sodíkové homeostázy, které budou nalezeny u těchto modelů hypertenze, mohou být použity při detailnější klasifikaci lidské hypertenze s cílem určit vhodnost hypertenzních pacientů pro jednotlivé terapeutické přístupy (od standardních farmakologických zásahů do RAS a SNS až po renální sympatickou denervaci).; Brain and kidney play essential role in the pathogenesis of hypertension. Sympathetic nervous system (SNS) is a principle effector in the brain regulation of vascular tone and is also responsible for abnormal renal function in salt-sensitive hypertension (ß2-WNK4-NCC pathway). In contrast, renin-angiotensin system (RAS) is a major regulator of renal function in salt-resistant hypertension. It also modulates sympathetic vasoconstriction by its central and peripheral action. The aim of this project is to evaluate the role of these systems (especially ß2-WNK4-NCC pathway) in the development of several forms of experimental hypertension resembling human salt-sensitive or salt-resistant hypertension. The differences in SNS and RAS control of blood pressure, renal function and sodium homeostasis revealed in particular models might be used in a more detailed classification of human hypertension in order to discern the eligibility of hypertensive patients for particular therapeutic interventions – from standard pharmacological intervention to RAS and SNS to renal sympathetic denervation.

• MeSH
• hypertenze patofyziologie   MeSH
• krevní tlak fyziologie   MeSH
• ledviny patofyziologie   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• renin-angiotensin systém fyziologie   MeSH
• sympatický nervový systém patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• kardiologie
• neurologie
• angiologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

Suboptimal conditions during prenatal and early postnatal development can increase risk of hypertension later in life. We studied consequences of a changed perinatal environment by initiating the cross-fostering of homozygous Ren-2 transgenic rat (TGR) offspring to normotensive, transgene-negative control mothers, and vice versa. We hypothesized that cross-fostering to a normotensive female can attenuate the development of malignant hypertension in TGR offspring (TGRx) and change their salt-sensitive response. Blood pressure (BP) was monitored by the telemetry system under normal salt intake, and BP responses to increased salt intake in the phase of established hypertension. Under normal salt conditions, BP was not markedly different in cross-fostered animals compared with controls. However, BP responses to 2% salt intake led to a stronger BP response in TGRx during the active phase when compared with the control TGR group. The TGRx also exhibited increased albuminuria, lower sodium excretion, and creatinine clearance under higher salt intake compared with control salt intake. Higher salt intake resulted in a significant increase of aldosterone concentrations only in the TGRx group; moreover, TGRx rats exhibited more pronounced renal injury compared with controls. In conclusion, our data indicate that cross-fostering in TGR not only did not attenuate the development of hypertension but, on the contrary, led to the deterioration of BP regulation, particularly due to exaggerated salt sensitivity and sodium retention in TGRx. Results underline the important role of the mother during lactation in postnatal development of the offspring, since these changes reflected different ion content in milk of a particular strain of rats.

• MeSH
• aldosteron krev   MeSH
• hypertenze genetika   patofyziologie   MeSH
• krevní tlak genetika   fyziologie   MeSH
• krysa rodu rattus MeSH
• ledviny patofyziologie   MeSH
• potkani transgenní MeSH
• renin-angiotensin systém fyziologie   MeSH
• renin genetika   MeSH
• sodík dietní * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Basal calcium sensitization is decreased in spontaneously hypertensive rats, although their blood pressure (BP) response to acute Rho-kinase inhibition is enhanced. Using fasudil (Rho-kinase inhibitor) or nifedipine (L-VDCC blocker), we evaluated the contribution of calcium sensitization and calcium entry to BP maintenance in hypertensive transgenic Ren-2 rats (TGR) focusing on the influence of major vasoactive systems and/or baroreflex efficiency on BP responses to these two drugs. Homozygous TGR and normotensive Hannover Sprague-Dawley (HanSD) control rats aged 5, 11, or 22 weeks were used. The acute BP-lowering effects of fasudil or nifedipine were studied in intact rats, nitric oxide-deficient L-NAME-pretreated rats and rats subjected to combined blockade of the renin-angiotensin system (RAS), sympathetic nervous system (SNS) and nitric oxide synthase (NOS). Fasudil- or nifedipine-induced BP reduction increased during hypertension development in TGR. By contrast, the nifedipine-induced BP response decreased, whereas the fasudil-induced BP response increased with age in HanSD controls. Our data indicated a major contribution of nifedipine-sensitive calcium entry and relative attenuation of calcium sensitization in hypertensive rats compared with normotensive controls. The BP responses to fasudil or nifedipine were enhanced by NOS inhibition and combined blockade in normotensive HanSD rats but not in hypertensive TGR. In conclusion, calcium sensitization is attenuated by endogenous nitric oxide in normotensive HanSD rats but not in hypertensive TGR. Moreover, BP reduction elicited by acute Rho-kinase inhibition is partially compensated by enhanced sympathetic vasoconstriction. The decreased compensation in hypertensive rats with impaired baroreflex efficiency explains their greater BP response to fasudil than in normotensive animals.

• MeSH
• 1-(5-isochinolinsulfonyl)-2-methylpiperazin analogy a deriváty   farmakologie   MeSH
• baroreflex účinky léků   fyziologie   MeSH
• blokátory kalciových kanálů farmakologie   MeSH
• hypertenze patofyziologie   MeSH
• krevní tlak účinky léků   fyziologie   MeSH
• krysa rodu rattus MeSH
• nifedipin farmakologie   MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• renin-angiotensin systém účinky léků   MeSH
• vazokonstrikce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In 2011 Fujita and coworkers proposed that ß-adrenergic stimulation causes decreased serine/threonine-protein kinase WNK4 transcription leading to the activation of Na-Cl cotransporter (NCC) which participates in salt sensitivity and salt hypertension development in rodents. The aim of our study was to investigate whether the above hypothesis is also valid for salt hypertension of Dahl rats, which are characterized by high sympathetic tone and abnormal renal sodium handling. Male 8-week-old salt-sensitive (SS/Jr) and salt-resistant (SR/Jr) Dahl rats were fed either low-salt diet (LS, 0.4 % NaCl) or high-salt diet (HS, 4 % NaCl) for 6 weeks. Half of the animals on either diet were chronically treated with non-selective ß-blocker propranolol (100 mg/kg/day). At the end of the experiment diuresis and sodium excretion were measured prior and after hydrochlorothiazide injection (HCTZ, 10 mg/kg i.p.). Furthermore, blood pressure (BP), heart rate (HR), sympathetic (pentolinium 5 mg/kg i.v.) and NO-dependent (L-NAME 30 mg/kg i.v.) BP components were determined. Chronic HS diet feeding increased BP through sympathoexcitation in SS/Jr but not in SR/Jr rats. Concomitant propranolol treatment did not lower BP in either experimental group. Under the conditions of low salt intake HCTZ increased diuresis, natriuresis and fractional sodium excretion in SR/Jr but not in SS/Jr rats. HS diet feeding attenuated renal response to HCT in SR/Jr rats, whereas no HCTZ effect was observed in SS/Jr rats fed HS diet. Propranolol treatment did not modify diuresis or natriuresis in any experimental group. In conclusions, our present data do not support the idea on the essential importance of renal ß-adrenergic-WNK4-NCC pathway in pathogenesis and/or maintenance of salt hypertension in Dahl rats.

• MeSH
• beta blokátory terapeutické užití   MeSH
• hypertenze chemicky indukované   farmakoterapie   metabolismus   MeSH
• krevní tlak účinky léků   fyziologie   MeSH
• krysa rodu rattus MeSH
• kuchyňská sůl aplikace a dávkování   škodlivé účinky   MeSH
• potkani inbrední Dahl MeSH
• propranolol farmakologie   terapeutické užití   MeSH
• protein-serin-threoninkinasy metabolismus   MeSH
• rodina nosičů rozpuštěných látek 12, člen 1 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Objective: Our previous study in heterozygous Ren-2 transgenic rats (TGR) demonstrated that long-term treatment with endothelin receptor A (ETA) blocker atrasentan added to the renin-angiotensin system (RAS) blockade had renoprotective effects in a model of chronic kidney disease (CKD) induced by partial nephrectomy. Since ETA blockade is known to cause edema, we were interested whether diuretic treatment added to this therapy would be beneficial. Design and Methods: Partial nephrectomy (NX) was performed at the age of 3 months in TGR rats which were subjected to: (i) RAS blockade alone (angiotensin receptor blocker losartan and angiotensin converting enzyme inhibitor trandolapril), (ii) combined RAS (losartan and trandolapril) and ETA receptor blockade (atrasentan), or (iii) diuretic (hydrochlorothiazide) added to the combined RAS + ETA blockade for 50 weeks following NX. Results: At the end of the study systolic blood pressure and cardiac hypertrophy were similarly decreased in all treated groups. Survival was significantly improved by ETA receptor blockade added to RAS blockade with no further effects of diuretic treatment. However, additional diuretic treatment combined with RAS + ETA blockade decreased body weight and had beneficial renoprotective effects - reductions of both kidney weight and kidney damage markers. Proteinuria gradually increased in rats treated with RAS blockade alone, while it was substantially lowered by additional ETA blockade. In rats treated with additional diuretic, proteinuria was progressively reduced throughout the experiment. Conclusion: A diuretic added to the combined RAS and ETA blockade has late renoprotective effects in CKD induced by partial nephrectomy in Ren-2 transgenic rats. The diuretic improved: renal function (evaluated as proteinuria and creatinine clearance), renal morphology (kidney mass, glomerular volume), and histological markers of kidney damage (glomerulosclerosis index, tubulointerstitial injury).

• Publikační typ
• časopisecké články MeSH

The effect of chemical sympathectomy on cardiovascular parameters and the compensatory role of adrenal hormones, the renin-angiotensin system, and cardiovascular sensitivity to vasoconstrictors were studied in spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats. Sympathectomy was induced in 20-week-old rats by daily intraperitoneal guanethidine administration (30 mg/kg b.w.) for 2 weeks. Basal blood pressure (BP), heart rate (HR), and restraint stress-induced cardiovascular changes were measured by radiotelemetry. The BP response to catecholamines was determined in rats with implanted catheters. Sympathectomy decreased BP only transiently, and after 14-day guanethidine treatment, BP returned to basal values in both strains. Sympathectomy permanently lowered HR, improved baroreflex sensitivity, and decreased the low-frequency domain of systolic blood pressure variability (a marker of vascular sympathetic activity). Guanethidine also attenuated the BP and HR responses to restraint stress. On the other hand, the BP response to catecholamines was augmented in sympathectomized rats, and this was not due to the de novo synthesis of vascular adrenergic receptors. Sympathectomy caused adrenal enlargement, enhanced the expression of adrenal catecholamine biosynthetic enzymes, and elevated plasma adrenaline levels in both strains, especially in WKY rats. Guanethidine also increased the plasma levels of aldosterone and corticosterone in WKY rats only. In conclusion, sympathectomy produced a transient decrease in BP, a chronic decrease in HR and improvement in baroreflex sensitivity. The effect of sympathectomy on BP was counteracted by increased vascular sensitivity to catecholamines in WKY rats and SHRs and/or by the enhanced secretion of adrenal hormones, which was more pronounced in WKY rats.

• MeSH
• baroreflex účinky léků   MeSH
• cévy účinky léků   inervace   patofyziologie   MeSH
• fyzické omezení MeSH
• guanethidin farmakologie   MeSH
• hypertenze patofyziologie   MeSH
• kardiovaskulární fyziologické jevy účinky léků   MeSH
• katecholaminy metabolismus   MeSH
• krevní tlak účinky léků   MeSH
• krysa rodu rattus MeSH
• nadledviny růst a vývoj   metabolismus   patofyziologie   MeSH
• potkani inbrední SHR MeSH
• potkani inbrední WKY MeSH
• psychický stres MeSH
• srdeční frekvence účinky léků   MeSH
• sympatolytika farmakologie   MeSH
• vazokonstriktory farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Our studies in hypertensive Ren-2 transgenic rats (TGR) demonstrated that chronic administration of atrasentan (ETA receptor antagonist) decreased blood pressure by reduced Ca2+ influx through L-type voltage-dependent calcium channels (L-VDCC) and attenuated angiotensin II-dependent vasoconstriction. We were interested whether bosentan (nonselective ET(A)/ET(B) receptor antagonist) would have similar effects. Young 4-week-old (preventive study) and adult 8-week-old (therapeutic study) heterozygous TGR and their normotensive Hannover Sprague-Dawley (HanSD) controls were fed normal-salt (NS, 0.6 % NaCl) or high-salt (HS, 2 % NaCl) diet for 8 weeks. An additional group of TGR fed HS was treated with bosentan (100 mg/kg/day). Bosentan had no effect on BP of TGR fed high-salt diet in both the preventive and therapeutic studies. There was no difference in the contribution of angiotensin II-dependent and sympathetic vasoconstriction in bosentan-treated TGR compared to untreated TGR under the condition of high-salt intake. However, bosentan significantly reduced NO-dependent vasodilation and nifedipine-sensitive BP component in TGR on HS diet. A highly important correlation of nifedipine-induced BP change and the BP after L-NAME administration was demonstrated. Although bosentan did not result in any blood pressure lowering effects, it substantially influenced NO-dependent vasodilation and calcium influx through L-VDCC in the heterozygous TGR fed HS diet. A significant correlation of nifedipine-induced BP change and the BP after L-NAME administration suggests an important role of nitric oxide in the closure of L-type voltage dependent calcium channels.

• MeSH
• antagonisté endotelinového receptoru farmakologie   MeSH
• bosentan farmakologie   MeSH
• heterozygot MeSH
• hypertenze farmakoterapie   genetika   metabolismus   patofyziologie   MeSH
• krevní tlak účinky léků   MeSH
• kuchyňská sůl * MeSH
• modely nemocí na zvířatech MeSH
• oxid dusnatý metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• renin genetika   MeSH
• vápníková signalizace účinky léků   MeSH
• vápníkové kanály - typ L metabolismus   MeSH
• vazodilatace účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Our previous studies demonstrated that chronic systemic blockade of renin-angiotensin system (RAS) lowered blood pressure (BP) of Ren-2 transgenic rats (TGR) by the attenuation of both angiotensin II-dependent and sympathetic vasoconstriction. Since systemic RAS blockade also inhibits brain RAS, we were interested which effects on these two types of vasoconstriction will have the central RAS blockade in hypertensive TGR rats. Adult male heterozygous TGR rats and their Hannover Sprague Dawley (HanSD) controls were subjected to chronic systemic or intracerebroventricular administration of either angiotensin type 1 receptor blocker losartan or direct renin inhibitor aliskiren for 4 weeks. Additional groups of TGR and HanSD rats were used for the evaluation of acute peripheral and brain effects of angiotensin II. Both chronic systemic and intracerebroventricular administrations of losartan or aliskiren normalized BP of TGR animals. BP effect of brain RAS blockade was based solely on the reduced sympathetic vasoconstriction, while systemic RAS blockade attenuated both angiotensin II-dependent and sympathetic vasoconstriction. Surprisingly, neither peripheral nor central pressor effects of acute angiotensin II administration were enhanced in TGR compared to HanSD rats. In conclusion, sympathoinhibition represents the main mechanism of BP reduction in heterozygous TGR rats subjected to chronic brain or systemic RAS blockade, while peripheral attenuation of angiotensin II-dependent vasoconstriction during systemic RAS blockade is less important. Our data suggest that the participation of angiotensin II in BP control of adult heterozygous TGR rats is shifted from peripheral vasoconstriction to central sympathoexcitation. Similar mechanisms cannot be excluded in human essential hypertension.

• MeSH
• angiotensin II aplikace a dávkování   farmakologie   MeSH
• blokátory receptorů AT1 pro angiotensin II farmakologie   MeSH
• heterozygot MeSH
• injekce intraventrikulární MeSH
• krevní tlak účinky léků   MeSH
• mozek patologie   MeSH
• oxid dusnatý metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• potkani transgenní MeSH
• receptor angiotensinu typ 1 metabolismus   MeSH
• renin-angiotensin systém účinky léků   MeSH
• srdce účinky léků   MeSH
• sympatický nervový systém účinky léků   MeSH
• vazokonstrikce účinky léků   MeSH
• velikost orgánu účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The insertion of mouse renin gene (Ren-2) into the genome of normotensive rats causes a spontaneous rise of blood pressure (BP), leading to an angiotensin II (Ang II)-dependent form of hypertension in transgenic (mRen-2)27 rats (TGR). However, enhanced sympathetic BP component was demonstrated in heterozygous TGR aged 20 weeks. In the present study we used another model, i.e. Cyp1a1-Ren-2 transgenic rats (iTGR) in which hypertension can be induced by natural xenobiotic indole-3 carbinol (I3C) added to the diet. We investigated whether the development of high blood pressure (BP) in 5-month-old iTGR animals fed I3C diet for 10 days is solely due to enhanced Ang II-dependent vasoconstriction or whether enhanced sympathetic vasoconstriction also participates in BP maintenance in this form of hypertension. Using acute sequential blockade of renin-angiotensin system (RAS), sympathetic nervous system (SNS) and NO synthase (NOS) we have demonstrated that the observed gradual increase of BP in iTGR fed I3C diet was entirely due to the augmentation of Ang II-dependent BP component without significant changes of sympathetic BP component. Thus, the hypertension in iTGR resembles to that of homozygous TGR in which high BP was entirely dependent on Ang II-dependent vasoconstriction. Moreover, our measurements of acute BP response to Rho kinase inhibitor fasudil in animals subjected to a combined blockade of RAS, SNS and NOS indicated the attenuation of basal calcium sensitization in both iTGR and homozygous TGR.

• MeSH
• angiotensin II genetika   metabolismus   MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• hypertenze genetika   patofyziologie   MeSH
• krevní tlak fyziologie   MeSH
• krysa rodu rattus MeSH
• potkani transgenní MeSH
• renin-angiotensin systém fyziologie   MeSH
• renin genetika   metabolismus   MeSH
• sympatický nervový systém fyziologie   MeSH
• vazokonstrikce fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Impressive advances in molecular genetic techniques allow to analyze the effects of natural selection on the development of human genome. For example, the trend towards blonde hair and blue eyes was documented. The approach to analyze possible effects of natural selection on the evolution of recent phenotypes with high risk of cardiovascular disease has not been described yet. A possible effect on the evolution of two main risk factors - hypercholesterolemia and hypertension - is presented. The close relationship of non-HDL cholesterol blood concentration to the proportion of pro-inflammatory macrophages in human visceral adipose tissue might be a result of long-lasting natural selection. Individuals with higher proportion of this phenotype might also display a higher ability to fight infection, which was very common in human setting from prehistory until Middle Ages. Successful battle against infections increased the probability to survive till reproductive age. Similar hypothesis was proposed to explain frequent hypertension in African Americans. A long-lasting selection for higher ability to conserve sodium during long-term adaptation to low sodium intake and hot weather was followed by a short-term (but very hard) natural selection of individuals during transatlantic slave transport. Only those with very high capability to retain sodium were able to survive. Natural selection of phenotypes with high plasma cholesterol concentration and/or high blood pressure is recently potentiated by high-fat high-sodium diet and overnutrition. This hypothesis is also supported by the advantage of familial hypercholesterolemia in the 19th century (at the time of high infection disease mortality) in contrast to the disadvantage of familial hypercholesterolemia during the actual period of high cardiovascular disease mortality.

• MeSH
• genom lidský genetika   MeSH
• kardiovaskulární nemoci epidemiologie   genetika   MeSH
• lidé MeSH
• molekulární evoluce * MeSH
• riziko MeSH
• selekce (genetika) genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH