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Cardiovascular diseases (CVDs) present high prevalence rates in the current world. It is estimated that approximately one-third of the global deaths are related to CVDs, and thus there is still a need for novel drugs to treat these disorders. We serendipitously discovered that LINS01005 (5a) is a potent vasodilating agent in rat aorta, and therefore a set of analogues were evaluated for the vasodilating potency in Wistar and SHR rat thoracic aorta precontracted with norepinephrine, with endothelium intact (E+) or denuded (E–) aortic rings. Compounds 5a and 5b were the most potent, showing submicromolar potency for endothelium intact vessels (EC50 853 and 941 nM, respectively) and micromolar values for E– vessels (EC50 2.4 and 7.1 µM, respectively). These compounds were indeed significantly more potent vasodilating agents in SHR-derived aortic rings (p

AB Introduction: Phalaris canariensis L. (Pc), known as birdseed, is rich in tryptophan. The aqueous extract of Pc (AEPc) treatment reduced systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR) via mechanisms mediated by the tryptophan metabolizing enzyme indoleamine 2,3-dioxygenase (IDO). Hypertension is a risk factor to cardiovascular and renal diseases. Considering that physical exercise improves hypertension and cardiovascular function, the aim of this study was to evaluate whether the benefits of exercise (Ex) would be enhanced by concomitant AEPc treatment (400 mg[middle dot]kg-1[middle dot]d-1 p.o.). Methods: Vascular reactivity was assessed in aorta rings from SHR treated with AEPc for 4 wk. Training intensity was based on maximal lactate steady state obtained during the 2-wk adaptation period in a treadmill running. Then exercised (60 min running, five times per week during 8 wk) or sedentary SHR were untreated or treated with AEPc during 8 wk. SBP was estimated by plethysmograph. Heart mass and body mass were used to obtain the index of cardiac hypertrophy. Glucose tolerance test was evaluated by oral glucose overload, and the mRNA expressions of indoleamine 2,3-dioxygenase, interleukin 1[beta] (IL-1[beta]), and IL-10 in the kidney were obtained by real time polymerase chain reaction. Results: AEPc induced endothelial-mediated vascular relaxation. AEPc or Ex alone reduced SBP, the index of cardiac hypertrophy and ventricular fibrosis, improved glucose metabolism, and attenuated proteinuria and the renal expression of the proinflammatory IL-1[beta] with an overexpression in the anti-inflammatory IL-10. AEPc potentiated the benefits of the Ex on the cardiovascular system, metabolic parameters, and renal inflammation. Conclusion: Birdseed reduced cardiovascular risk related to hypertension and had positive effects when associated to physical exercise. (C) 2016 American College of Sports Medicine

We evaluated cardiac autonomic modulation by heart rate (HRV), and arterial pressure variability (APV), and metabolic response in streptozotocin diabetic rats treated with green tea. Male Wistar rats were separated in groups: control, drinking tap water (C), green tea-treated (GT) group, diabetic, drinking tap water (D), and diabetic, treated with green tea (DGT). Kidney mass was greater in D and DGT than in C and GT, but reduced in DGT compared to D. Green tea prevented the increase in creatinine clearance and reduced hyperglycemia in DGT compared to D. Arterial pressure was increased in GT and decreased in D compared to C. HRV was reduced in D compared with all groups. APV was decreased in D compared to C and recovery in DGT. Sympathetic modulation of APV was decreased in D compared with all groups. Green tea reduced hyperglycemia, prevented renal injury and autonomic dysfunction, suggesting reduced cardiovascular risk and target organ damage in diabetes.

INTRODUÇÃO: A elevação do índice de massa corporaleapresençadesíndromemetabólica se associam com diminuição da função renal e o aparecimento de doença renal terminal. OBJETIVO: Avaliar o efeito da sobreposição de um modelo de obesidade experimental e hipertensão arterial sobre a pressão arterial, peso corporal e parâmetros metabólicos e renais de ratos. MÉTODOS: Foram estudados ratos machos das cepas Wistar e espontaneamente hipertensos (SHR). Os grupos MSG receberam glutamato monossódico no período neonatal (WST + MSG e SHR + MSG). Os animais controles receberam salina no período neonatal (WST e SHR). Após completarem três meses de vida, por 12 semanas foram pesados e tiveram a pressão arterial de cauda aferida semanalmente. A determinação de microalbuminúria foi realizada nas semanas 0, 4, 8 e 12. Ao final do período de acompanhamento, coletou-se sangue para glicemia de jejum, creatinina e perfil lipídico. Os rins foram retirados, corados e o índice de esclerose glomerular foi calculado. RESULTADOS: A administração de MSG produziu maior ganho percentual de peso corporal, elevação da glicemia de jejum e maior grau de lesão glomerular nos ratos WST -MSG e SHR -MSG quando comparados aos seus controles. Houve maior excreção urinária de albumina nos ratos do Grupo SHR + MSG quando comparados aos SHR. Não houve diferença estatística na pressão arterial de cauda, creatinina e parâmetros do metabolismo lipídico. CONCLUSÕES: A associação de obesidade neuroendócrina e a hipertensão arterial promoveram alterações morfológicas e funcionais no glomérulo mais severas do que aquelas observadas nos ratos somente hipertensos. INTRODUCTION: Increased body mass index and the metabolic syndrome are associated with decreased renal function and the development of end-stage kidney disease. OBJECTIVE: To evaluate the effect of the overlap between an experimental model of obesity and genetic hypertension on the blood pressure, body weight and metabolic and kidney parameters of rats. METHODS: We studied male rats of the Wistar (WST) and spontaneously hypertensive rats (SHR) strains. Monosodium glutamate (MSG) was administered in the neonatal period to both strains, to make up two groups: WST + MSG and SHR + MSG. Animals in the control groups (WST and SHR) received saline. After completing three months of life, a 12-week follow-up period ensued, during which bi-weekly measurements of body weight (BW) and tail-cuff blood pressure (TCBP) were obtained. Microalbuminuria was analyzed at weeks 0, 4, 8 and 12. At the end of the follow-up period, blood was obtained for fasting glucose, plasma creatinine, and lipid profile determinations. The kidneys were removed, stained, and the glomerular sclerosis index was calculated. RESULTS: The administration of MSG produced higher percentage body weight gain, higher fasting blood glucose and a higher degree of glomerular injury in WST-MSG and MSG-SHR rats, compared to their controls. Greater urinary albumin excretion was observed in SHR + MSG rats, when compared to SHR. There was no statistical difference in the TCBP, creatinine, and lipid profile. CONCLUSIONS: The association of neuroendocrine obesity and arterial hypertension promoted morphological and functional changes in the glomerulus. These changes were more severe than those observed in hypertensive-only rats.

OBJETIVOS: Produzir um modelo experimental de síndrome metabólica (SM) e analisar efeitos da metformina sobre pressão arterial (PA), peso corporal (PC), metabolismo glicídico e conteúdo de gordura epididimal (GE). MÉTODO: Os machos SHR receberam 2 mg/kg/dia de glutamato monossódico (MSG) até o 11º dia de vida. Os controles receberam salina. Após 12 semanas, foram separados em dois grupos e tratados com 500 mg/kg/dia de metformina ou veículo. Foram acompanhados a PA e o PC dos dois grupos. Ao final do seguimento, realizou-se o teste de tolerância à glicose oral (TTGO) e mediu-se o índice de sensibilidade à insulina. Após sacrifício dos animais, a GE foi pesada. RESULTADOS: A administração de MSG intensificou a resistência insulínica e aumentou o conteúdo de GE, sem, no entanto, alterar a PA. O tratamento com metformina promoveu melhora da sensibilidade insulínica e redução da GE e PA. CONCLUSÕES: Observou-se importante papel da resistência hepática à insulina na SM e efeitos cardiovasculares benéficos da melhora na sensibilidade insulínica.

O objetivo do estudo foi avaliar o efeito da obesidade induzida pela administração neonatal de glutamato monossódico (MSG) sobre o peso corporal, a pressão arterial de cauda, a hemodinâmica sistêmica e a função ventricular esquerda de ratos Wistar. Dois grupos de ratos Wistar foram preparados: a)18 animais foram tornados obesos por meio da administração de 2 mg/kg/SC de MSG durante os 11 primeiros dias do período neonatal e b)16 animais controles (que receberam o veículo do MSG pelo mesmo período). Animais adultos foram acompanhados dos três aos seis meses de vida e tiveram pressão arterial e peso corporal medidos duas vezes por semana. Ao final desse período, em parte dos animais dos dois grupos, avaliou-se a função ventricular por intermédio da preparação do coração isolado de Langerdorff, e os animais restantes foram usados para o estudo da hemodinâmica sistêmica por meio de um método de termodiluição. Resultados: Nos animais MSG houve aumento da gordura epididimal relativa (WST = 2,076 ± 0,622; MSG = 2,731 ± 0,722 g/100 g), aumento significante da freqüência cardíaca (WST = 235,0 ± 35,1; MSG = 312,0 ± 90,8 bpm), da resistência periférica total (WST = 0,312 ± 0,100; MSG = 0,535 ± 0,195 mmHg.ml-1.min), e diminuição do volume sistólico (WST = 1,020 ± 0,364; MSG = 0,748 ± 0,455 µl/bat). No estudo hemodinâmico, também detectou-se nos animais obesos aumento da pressão arterial média. Os aumentos da FC e da RPT e a diminuição do VS sugerem que houve aumento da atividade simpática nos ratos normotensos com obesidade associado ao aumento da deposição de gordura visceral. The aim of this study was to evaluate the effects of obesity induced by neonatal Monosodium Glutamate (MSG) administration upon body weight, tail blood pressure, systemic hemodynamics and left ventricular function of Wistar rats. Two groups of Wistar rats were prepared: a) 18 animals made obese through the administration of 2mg/Kg/SC of MSG during the first 11 days of the neonatal period and b)16 control animals (vehicle treated for the same period). Adults animals were followed from the 3rd up the 6th month of life with blood pressure and body weight being measured twice a week. At the end of this period, in part of animals from both groups, we evaluated the left ventricular function through the Langendorff isolated heart preparation whereas the remainders were used to evaluate the systemic hemodynamics through a termodilution method. Results: MSG animals showed significant increases in heart rate (WST = 235,0 ± 35,1; MSG = 312,0 ± 90,8 bpm), total peripheral resistance (WST = 0,312 ± 0,100; MSG = 0,535 ± 0,195 mmHg.ml-1.min) and in relative epididymal adipose tissue content (WST = 2,076 ± 0,622; MSG = 2,731 ± 0,722 g/100g) and a reduction of systolic volume (WST = 1,020 ± 0,364; MSG = 0,748 ± 0,455 ml/bat). An increase in mean arterial pressure was also detected in obese animals during the hemodynamic evaluation. The increases in HR and TPR and the reduction in SV suggest an augmentation in the sympathetic activation of those obese normotensive rats associated with an increased visceral fat deposition.

Introducao: Ainda e controverso se ocorre sinergismo entre as diferentes medidas nao farmacologicas utilizadas no tratamento da hipertensao arterial. Objetivo: Avaliar o efeito do exercicio fisico aerobico, da sobrecarga oral de potassio e da sua associacao sobre a pressao arterial, metabolismo glicidico, excrecao urinaria de albumina e morfologia glomerular de ratos espontaneamente hipertensos (SHR). Metodos: SHRs foram divididos em: Grupo Controle (SHR; dieta padrao e sedentario, n = 10); Grupo Exercicio (SHR + E; treinado em esteira rolante, dieta padrao, n = 10), Grupo Potassio (SHR + K; sedentario, dieta rica em potassio, n = 10) e Grupo Exercicio + Potassio (SHR + E + K; exercitado, dieta rica em potassio, n = 10). Semanalmente, foi aferido o peso corporal (PC) e a pressao arterial de cauda (PAC). Ao final de 16 semanas, foi realizado o Teste de Tolerância oral a Glicose. A albuminuria foi determinada nos periodos basal, na 8a e 16a semana. Apos o sacrificio, foi realizada a analise do indice de esclerose glomerular e a pesagem da gordura visceral. Resultados: A PAC e o PC nao variaram significativamente. Houve melhora da sensibilidade a insulina no Grupo Exercicio e Grupo Potassio, mas nao no Grupo Exercicio + Potassio. Na 16a semana, a albuminuria de todos os grupos foi significativamente menor que o grupo SHR Controle. O indice de esclerose glomerular e o peso da gordura visceral tambem foram significativamente menores em todos os grupos tratados quando comparados ao controle. Conclusao: A dieta rica em potassio e o exercicio fisico determinaram melhora no metabolismo glicidico, na albuminuria e na morfologia glomerular, porem, a sobreposicao dos tratamentos nao apresentou sinergismo.

It is still controversial whether there are synergistic effects among different non-pharmacological interventions used in the treatment of hypertension.To evaluate the effect of aerobic exercise, oral supplementation of potassium and their combination on blood pressure, glucose metabolism, urinary albumin excretion and glomerular morphology in spontaneously hypertensive rats (SHR).SHR were divided into groups: Control Group (SHR; standard diet and sedentary, n = 10), Exercise Group (SHR + E; trained on a treadmill, standard diet, n = 10), Potassium Group (SHR + K; sedentary, potassium supplementation, n = 10) and Group Exercise + Potassium (SHR + E + K, exercise, potassium supplementation n = 10). Weekly, body weight (BW) and tail blood pressure (TAP) were measured. At the end of 16 weeks, a Oral Glucose Tolerance Test was performed. Albuminuria was determined in the baseline period, at 8th and at 16th week. After sacrifice, the analysis of glomerular sclerosis index and visceral fat weight was performed.The TAP and BW did not change significantly. There was improvement in insulin sensitivity in SHR + E and SHR + K, but not in SHR + E + K. At week 16, albuminuria in all groups was significantly lower than the SHR control. The glomerular sclerosis index and visceral fat content were also significantly lower in all groups compared to control.An oral supplementation of potassium and exercise led to an improvement in glucose metabolism, in albuminuria and glomerular morphology, however, the overlap of the treatments did not show synergism.

Abstract The neurotransmitter substance P acts also as a potent vasodilator. Its participation in the pathogenesis of deoxycorticosterone acetate (DOCA)–salt hypertension was evaluated by an acute infusion of a newly synthesized, potent, specific nonpeptide antagonist of substance P at the NK-1 receptor, the agent CP 96 345. In conscious unrestrained rats, CP 96 345 induced significant and sustained increases in mean arterial pressure of DOCA-salt rats but only small, transient, and nonsignificant rises in blood pressure of sham-treated control rats. The rise in blood pressure was not accompanied by changes in heart rate. Maximal blood pressure increase in DOCA-salt rats was 31.7±14.8 mm Hg. In a second series of experiments, the hemodynamic effects of this antagonist were evaluated under anesthesia in both DOCA-salt and sham-treated control rats by the thermodilution method. During CP 96 345 infusion, sustained increases in cardiac index and stroke volume and decreases in total peripheral resistance were observed in both DOCA-salt and control rats. In DOCA-salt rats, cardiac index rose by 79.4%, while total peripheral resistance fell by 27.9% of the baseline values. In control rats, the changes were smaller (+27.2% and −22.5%, respectively). Stroke volume changed in parallel to cardiac output in both groups. The data suggest that acute blockade of NK-1 receptors increases blood pressure in DOCA-salt rats mainly by an increase in cardiac output. We conclude that endogenous substance P tends to counteract the DOCA-salt–induced elevation of blood pressure by modulating both cardiac output and peripheral resistance.

Abstract The purpose of these experiments was to determine in normotensive rats the role of endogenous bradykinin, prostaglandins, and nitric oxide in glucose metabolism and blood pressure response to hyperinsulinemia. Normotensive Wistar rats were treated with two different bradykinin antagonists, indomethacin or N ω -nitro- l -arginine methyl ester, concurrently with a euglycemic clamp with insulin infusion rates of 3 or 6 mU/kg per minute. Glucose uptake, steady-state plasma insulin levels, and insulin sensitivity index were determined over 2 hours. Bradykinin inhibition dramatically reduced glucose uptake and insulin sensitivity index during both the lower and higher insulin infusion rates to 30% and 32%, respectively, of values observed in control rats. Inhibition of prostaglandins or nitric oxide did not alter glucose metabolism in these rats. Blood pressure remained unchanged in the control group throughout the clamp but increased significantly in rats submitted to inhibition of bradykinin, prostaglandins, or nitric oxide, suggesting that these vasodilator systems tend to counteract the hypertensive effect of hyperinsulinemia. The counterregulatory component attributable to bradykinin was about twice as great as that attributable to nitric oxide. These findings suggest that insulin infusion in normotensive Wistar rats fails to raise blood pressure because its effects are offset by mobilization of vasodilator mechanisms, such as bradykinin, prostaglandins, and nitric oxide. Bradykinin seems to play the most important homeostatic role under these conditions, because its inhibition significantly reduces insulin sensitivity and allows blood pressure to rise.

OBJETIVO: Avaliar a indução do diabetes melito tipo 1 (DM1) na hemodinâmica sistêmica e função ventricular de ratos normotensos e hipertensos. MATERIAIS E MÉTODOS: O DM1 foi induzido por estreptozotocina em ratos Wistar (WST), borderline hypertensive rats (BHR) e spontaneously hypertensive rats (SHR). A hemodinâmica sistêmica foi avaliada por termodiluição e a função ventricular, pela preparação de Langendorff. RESULTADOS: A indução de DM1 produziu aumento na pressão arterial de WST e BHR. O DM1 determinou aumento na resistência periférica total no grupo WST e diminuição do débito cardíaco e do volume sistólico nos grupos WST e BHR. Índices de função sistólica foram reduzidos e a rigidez ventricular, apenas nos ratos WST diabéticos. Todos esses efeitos foram mais proeminentes nos ratos WST diabéticos. CONCLUSÃO: O DM1 foi acompanhado por importantes alterações nas funções sistólica e diastólica, levando a uma diminuição nos valores hemodinâmicos sistêmicos que não foram alterados pela hipertensão arterial. OBJECTIVE: To analyze the effects of type-1 diabetes mellitus (DM1) induction on systemic hemodynamic and ventricular function of normotensive and hypertensive rats. MATERIALS AND METHODS: DM1 was induced by streptozotocin in Wistar rats (WST), borderline hypertensive rats (BHR) and spontaneously hypertensive rats (SHR). The systemic hemodynamic was evaluated by thermodilution and ventricular function by Langendorff preparation. RESULTS: DM1-induction increased tail arterial pressure of WST and BHR. DM1 also increased total peripheral resistance in WST and decrease in cardiac output stroke volume in WST and BHR. Systolic function indexes were reduced and ventricular stiffness increased in all WST-diabetic rats. All of these effects were more prominent on diabetic WST rats. CONCLUSION: The DM1 in rats was accompanied by important changes in both systolic and diastolic heart function leading to significant changes in the systemic hemodynamics that were not significantly enhanced by hypertension. Universidade Federal de São Paulo (UNIFESP) Pontifícia Universidade Católica de São Paulo Departamento de Ciências Fisiológicas UNIFESP, EPM SciELO

OBJETIVO: Estudar dois modelos de obesidade, exócrina e endócrina, e sua associação sobre a pressão arterial de cauda (PAC), o peso corporal (PC), o metabolismo glicídico (ISI) e gordura epididimal relativa (GER). MÉTODOS: Foram estudados ratos machos da cepa Wistar. O grupo MSG recebeu glutamato monossódico no período neonatal. Aos 3 meses de idade parte desses animais passou a receber dieta cafeteria (CAF). Os animais receberam controle salina no período neonatal. Durante 12 semanas foram pesados (PC) e tiveram a pressão arterial de cauda (PAC) aferida. O Teste de Tolerância Oral à Glicose foi realizado e o Índice de Sensibilidade à Insulina (ISI), calculado. O peso ventricular relativo (PVR) e a gordura epididimal relativa (GER) também foram calculados. RESULTADOS: Não se verificou alterações no PC e na PAC. A obesidade induzida pela administração de MSG e CAF, isoladamente, promoveu aumento da resistência à insulina (WST = 23,25 ± 9,31; CAF = 15,92 ± 9,10*; MSG = 13,41 ± 3,84* mg-1mU-1, p < 0,05 vs WST) e da gordura visceral (WST = 6,20 ± 0,57; CAF = 8,27 ± 1,53*; MSG = 8,23 ± 1,98* g/100 g, *p < 0,05), quando esses animais foram comparados com os controles. A associação de ambos os modelos de obesidade produziu um efeito sinérgico sobre a resistência à insulina (MSG+CAF = 9,34 ± 5,77 mg-1mU-1, p

To analyze the effects of type-1 diabetes mellitus (DM1) induction on systemic hemodynamic and ventricular function of normotensive and hypertensive rats.DM1 was induced by streptozotocin in Wistar rats (WST), borderline hypertensive rats (BHR) and spontaneously hypertensive rats (SHR). The systemic hemodynamic was evaluated by thermodilution and ventricular function by Langendorff preparation.DM1-induction increased tail arterial pressure of WST and BHR. DM1 also increased total peripheral resistance in WST and decrease in cardiac output stroke volume in WST and BHR. Systolic function indexes were reduced and ventricular stiffness increased in all WST-diabetic rats. All of these effects were more prominent on diabetic WST rats.The DM1 in rats was accompanied by important changes in both systolic and diastolic heart function leading to significant changes in the systemic hemodynamics that were not significantly enhanced by hypertension.

To study two different models of obesity, exocrine and endocrine, and its association on tail arterial pressure (TAP), body weight (BW), glucose metabolism and visceral fat content.Male Wistar rats were studied. The MSG group was composed by rats that received of MSG in neonatal period. At the 3rd month of life, part of these animals received cafeteria diet. Animals received saline control in the neonatal period. In the 12 weeks of study, body weight and blood pressure were measured twice a week. In the end of this period on, Oral Glucose Tolerance Test (OGTT) was performed and the Insulin Sensitivity Index (ISI) was calculated, also the left Relative Ventricular Weight (RLW) and Relative Epididimal Fat Weight (REFW) were obtained.No changes on BW and TAP were verified. The obesity induced by MSG and CAF, individually, let to increases on insulin resistance (WST = 23,25 ± 9,31; CAF = 15,92 ± 9,10*; MSG = 13,41 ± 3,84* mg-1mU-1, p0,05 vs WST) and relative epididimal fat content (WST = 6,20 ± 0,57; CAF = 8,27 ± 1,53*; MSG = 8,23 ± 1,98* g/100 g, *p0,05) when these rats were compared to control rats. An enhanced effect upon these parameters was observed with the association of both obesity models (MSG+CAF = 9,34 ± 5,77 mg-1mU-1, p0,05 vs MSG and CAF) and visceral fat content (MSG+CAF = 11,12 ± 3,85 g/100g, p0,05 vs MSG and CAF).The association of these two experimental models of obesity aggravates insulin resistance that probably is due at least in part to the increase of visceral fat content.

To make available experimental model for the metabolic syndrome (MS) and verify effects of chronic oral treatment with metformin upon blood pressure (BP), body weight (BW), glucose metabolism, epididimal fat content (EF).Males SHR received monossodium glutamate (MSG, 2 mg/kg/day/sc) during first 11 days of life. Control animals received saline. After 12 weeks, animals were separated in two groups, treated either with metformin 500 mg/ kg/day or vehicle during 12 weeks. PA and BW were determined. At the end of the follow-up, animals underwent an oral glucose tolerance test (OGTT) and insulin sensitivity index was determined. Upon sacrifice EF was measured.MSG worsened insulin resistance and induced visceral obesity in SHR, without change BP. Treatment with metformin improved glucose metabolism and reduces EF and BP.These observations emphasize the role of hepatic insulin resistance on MS and point out for beneficial cardiovascular effects with improvement in the insulin sensitivity.

The aim of this study was to evaluate the effects of obesity induced by neonatal Monosodium Glutamate (MSG) administration upon body weight, tail blood pressure, systemic hemodynamics and left ventricular function of Wistar rats. Two groups of Wistar rats were prepared: a) 18 animals made obese through the administration of 2 mg/Kg/SC of MSG during the first 11 days of the neonatal period and b)16 control animals (vehicle treated for the same period). Adults animals were followed from the 3rd up the 6th month of life with blood pressure and body weight being measured twice a week. At the end of this period, in part of animals from both groups, we evaluated the left ventricular function through the Langendorff isolated heart preparation whereas the remainders were used to evaluate the systemic hemodynamics through a termodilution method.MSG animals showed significant increases in heart rate (WST=235.0+/-35.1; MSG=312.0+/-90.8 bpm), total peripheral resistance (WST=0.312+/-0.100; MSG=0.535+/-0.195 mmHg.ml(-1).min) and in relative epididymal adipose tissue content (WST=2.076+/-0.622; MSG=2.731+/-0.722 g/100 g) and a reduction of systolic volume (WST=1.020+/-0.364; MSG=0.748+/-0.455 microl/bat). An increase in mean arterial pressure was also detected in obese animals during the hemodynamic evaluation. The increases in HR and TPR and the reduction in SV suggest an augmentation in the sympathetic activation of those obese normotensive rats associated with an increased visceral fat deposition.

The participation of substance P in the pathogenesis of five models of experimental hypertension, ie, DOCA-salt, subtotal nephrectomy, one-kidney-one clip renovascular, two-kidney-one clip renovascular, and spontaneous hypertension, was evaluated via an acute infusion of a newly synthesized potent, specific nonpeptide antagonist of substance P at the NK-1 receptor, the agent CP 96,345. In conscious unrestrained rats, CP 96,345 induced significant and sustained increases in mean arterial pressure of DOCA-salt, subtotal nephrectomy, and one-kidney-one clip renovascular hypertensive rats but only small and nonsignificant changes in blood pressure of two-kidney-one clip renovascular and spontaneously hypertensive rats. CP 96,345 had no effect on the blood pressure of sham-treated controls and Wistar-Kyoto rats. This NK-1 receptor antagonist did not significantly affect the heart rate of any experimental model studied. The data suggest that endogenous substance P may act as a partial counterregulatory mechanism against vasoconstriction in models of salt-dependent hypertension.