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1.
Arch Intern Med ; 144(8): 1581-4, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6466017

RESUMO

A controlled prospective study compared two groups of obese hypertensive subjects during 12 weeks of a hypocaloric protein-supplemented fast containing 40 mEq of sodium daily. One group received additional sodium chloride sufficient to maintain baseline sodium intake measured prior to the fast (210 m/Eq/day). Sodium restriction resulted in greater weight loss and slightly greater BP reduction only during the initial week of fasting. Thereafter, despite sodium equilibrium, further substantial weight loss and BP reduction were identical in both groups, the decrement in weight being linear (1.89 kg/wk) and the BP reduction asymptotic. Although the initial reduction in BP during the first week of supplemented fast may be attributable to negative salt and water balance, the further reduction in BP during a period of constant sodium balance must be caused by weight loss per se or by the triggering of other antihypertensive mechanisms associated with weight reduction.


Assuntos
Pressão Sanguínea , Peso Corporal , Dieta Hipossódica , Hipertensão/dietoterapia , Obesidade/dietoterapia , Dieta Redutora , Jejum , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Natriurese , Obesidade/fisiopatologia , Estudos Prospectivos , Cloreto de Sódio/administração & dosagem , Fatores de Tempo , Equilíbrio Hidroeletrolítico
2.
Hypertension ; 17(6 Pt 2): 965-8, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2045177

RESUMO

To investigate the effects of a low calorie regimen on sympathetic function and its relation to blood pressure response, 22 untreated obese essential hypertensive patients (50 +/- 2 years, body mass index 29 +/- 1 kg/m2) were hospitalized and a diet was prescribed of 2,000 kcal/day for 5 days (control period) followed by 800 kcal/day for 21 days without changing salt intake (8-10 g/day). The dose of intravenous phenylephrine infusion needed to elevate systolic blood pressure 20 mm Hg (CD20) and the 24-hour urinary excretion of norepinephrine (UNE) were measured. During the low calorie period, blood pressure normalized in 14 patients (responder group, 124 +/- 3/79 +/- 4 mm Hg) and eight remained hypertensive (poor responder group, 158 +/- 6/103 +/- 3 mm Hg). At the control period, blood pressure and body mass index were similar, but the responder group had higher UNE (134 +/- 15 micrograms/day) and CD20 (127 +/- 11 micrograms) than the poor responder group (89 +/- 6 micrograms/day and 79 +/- 13 micrograms, respectively). During the low calorie period, both UNE (87 +/- 15 micrograms/day) and CD20 (74 +/- 10 micrograms) decreased in the responder group; no change was seen in the poor responder group. Changes in UNE and systolic blood pressure were correlated (r = 0.6, p less than 0.05). In conclusion, suppression of sympathetic activity plays a role in blood pressure reduction during moderate caloric restriction.


Assuntos
Pressão Sanguínea/fisiologia , Ingestão de Energia , Sistema Nervoso Simpático/fisiopatologia , Índice de Massa Corporal , Feminino , Humanos , Hipertensão/dietoterapia , Hipertensão/fisiopatologia , Hipertensão/urina , Masculino , Pessoa de Meia-Idade , Norepinefrina/urina , Obesidade/dietoterapia , Obesidade/fisiopatologia , Obesidade/urina
3.
Hypertension ; 31(1 Pt 2): 321-7, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9453323

RESUMO

Abnormalities in fibrinolysis, endothelial function, and glucose and lipid metabolism have been reported in hypertension. This study was conducted to examine the interrelationships between fibrinolytic factors, glucose and lipid metabolism, and endothelial function in hypertension. The effects of administering an angiotensin converting enzyme inhibitor, benazepril, were also examined. Blood levels of the following substances were measured in patients with borderline and mild hypertension (n=50, 51+/-19 years) and in age-matched controls (n=10): total cholesterol, triglycerides, tissue plasminogen activator activity and antigen, and plasminogen activator inhibitor type 1 activity and antigen. Insulin sensitivity was assessed by oral glucose tolerance test, and endothelial function was assessed by evaluating changes in diameter of the brachial artery during reactive hyperemia as observed by ultrasonography. Activities of tissue plasminogen activator and plasminogen activator inhibitor type 1 were both elevated in the hypertensive patients. Stepwise multiple regression analysis showed that plasminogen activator inhibitor type 1 antigen correlated with insulin sensitivity, total cholesterol levels, and triglycerides levels (P<.01). Endothelial function was negatively correlated with tissue plasminogen activator activity and antigen (P<.01). The chronic administration of benazepril (5-10 mg/d) for 20 weeks improved insulin sensitivity, endothelial function (6.6+/-3.4-->9.0+/-2.5%, P<.01), and tissue plasminogen activator activity and antigen. These results indicate that abnormalities in fibrinolysis are associated with endothelial dysfunction as well as disorders of glucose and lipid metabolism in patients with borderline and mild hypertension. The treatment of such patients with benazepril appeared to improve the impairment in fibrinolysis and endothelial dysfunction.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Benzazepinas/uso terapêutico , Endotélio Vascular/fisiopatologia , Fibrinólise , Hipertensão/fisiopatologia , Adulto , Anlodipino/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Artéria Braquial , Bloqueadores dos Canais de Cálcio/uso terapêutico , Artérias Carótidas/diagnóstico por imagem , Colesterol/sangue , Ecocardiografia , Endotélio Vascular/fisiologia , Feminino , Teste de Tolerância a Glucose , Hemostasia , Humanos , Hiperemia , Hipertensão/diagnóstico por imagem , Hipertensão/tratamento farmacológico , Insulina/fisiologia , Masculino , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/sangue , Valores de Referência , Análise de Regressão , Ativador de Plasminogênio Tecidual/sangue , Triglicerídeos/sangue
4.
Hypertension ; 20(5): 596-600, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1428109

RESUMO

We investigated the role of insulin in salt-sensitive hypertension in Dahl salt-sensitive and salt-resistant rats. The rats were kept in metabolic cages, and sodium intake and urinary sodium excretion were measured. In salt-sensitive rats receiving a 0.3% NaCl diet, sodium retention was significantly greater at weeks 1 and 2 in rats that received an insulin infusion than in those receiving a saline infusion. Mean arterial blood pressure and plasma norepinephrine levels were significantly higher at week 3 in insulin-treated rats than in saline-treated rats (mean arterial pressure, 137 +/- 3 mm Hg versus 119 +/- 3 mm Hg, p < 0.05; plasma norepinephrine, 0.40 +/- 0.02 ng/ml versus 0.27 +/- 0.01 ng/ml, p < 0.05). Insulin did not influence sodium retention, mean arterial pressure, or plasma norepinephrine in salt-resistant rats. Coadministration of an alpha-blocker (bunazosin, 10 mg/kg per day for 3 weeks) in salt-sensitive rats abolished the insulin-induced elevations in mean arterial pressure and sodium retention. When salt-sensitive rats were fed a low salt diet (0.03% NaCl), insulin did not raise mean arterial pressure. Thus, insulin elevated blood pressure only in the salt-sensitive model. The sympathetic nervous system and sodium retention in the early phase of insulin overload may contribute to elevation of mean arterial pressure in this model.


Assuntos
Pressão Sanguínea , Hiperinsulinismo/fisiopatologia , Cloreto de Sódio/farmacologia , Animais , Resistência a Medicamentos/genética , Hiperinsulinismo/sangue , Hiperinsulinismo/urina , Insulina/sangue , Masculino , Natriurese , Norepinefrina/sangue , Ratos , Ratos Endogâmicos
5.
Hypertension ; 23(4): 450-5, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8144214

RESUMO

Although angiotensin converting enzyme inhibitors and alpha 1-blockers have been reported to improve insulin sensitivity, their mechanisms of action have not been elucidated. To investigate the role of kinins in insulin sensitivity, we treated 4-week-old spontaneously hypertensive rats with either an angiotensin converting enzyme inhibitor (enalapril), an alpha 1-blocker (doxazosin), or an angiotensin II antagonist (losartan) for 3 weeks. A control group received no drugs. In addition, 18 rats treated with enalapril or doxazosin received a simultaneous administration of a kinin antagonist (Hoe 140). Glucose clamp testing was performed in each group. Enalapril (128 +/- 1 mmHg) and doxazosin (132 +/- 2 mmHg) decreased mean blood pressure compared with control levels (148 +/- 1 mmHg) (P < .01). The glucose requirement for the clamp test during the administration of enalapril (25.8 +/- 0.5 mg/kg per minute) or doxazosin (28.6 +/- 0.7 mg/kg per minute) was higher than that of the control group (19.8 +/- 0.5 mg/kg per minute) (P < .05). Although Hoe 140 did not alter the glucose requirement of doxazosin (27.8 +/- 0.5 mg/kg per minute), it decreased that of enalapril (22.6 +/- 0.9 mg/kg per minute) (P < .05) without affecting the changes in mean blood pressure induced by enalapril. In addition, losartan decreased mean blood pressure but did not affect the glucose requirement. Thus, the improvement in insulin sensitivity produced by an angiotensin converting enzyme inhibitor is mostly dependent on kinins but not on angiotensin II antagonism, and an alpha 1-blocker improves insulin sensitivity irrespective of kinins.


Assuntos
Enalapril/uso terapêutico , Hipertensão/tratamento farmacológico , Insulina/farmacologia , Cininas/fisiologia , Análise de Variância , Angiotensina II/antagonistas & inibidores , Animais , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Compostos de Bifenilo/farmacologia , Compostos de Bifenilo/uso terapêutico , Glicemia/análise , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Bradicinina/análogos & derivados , Bradicinina/antagonistas & inibidores , Bradicinina/farmacologia , Bradicinina/fisiologia , Doxazossina/farmacologia , Doxazossina/uso terapêutico , Enalapril/farmacologia , Técnica Clamp de Glucose , Hipertensão/metabolismo , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Insulina/sangue , Cininas/antagonistas & inibidores , Losartan , Masculino , Potássio/sangue , Ratos , Ratos Endogâmicos SHR , Sódio/sangue , Tetrazóis/farmacologia , Tetrazóis/uso terapêutico
6.
Hypertension ; 36(2): 245-9, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10948085

RESUMO

Hypertension is frequently accompanied by left ventricular hypertrophy, endothelial dysfunction, and abnormal glucose metabolism. However, no study has examined the relative pathological significance of left ventricular hypertrophy and abnormal glucose metabolism on endothelial dysfunction in hypertension. This study was conducted to evaluate whether abnormal glucose tolerance assessed by 75-g oral glucose tolerance test or left ventricular hypertrophy is more closely associated with endothelial dysfunction in never-treated hypertensive patients without elevated fasting blood glucose. We studied 107 unmedicated hypertensive patients (mean age, 54+/-10 years) whose fasting blood glucose was <7.0 mmol/L. Endothelial function was assessed by change in brachial artery diameter in response to reactive hyperemia, and left ventricular mass index was determined by ultrasonography. Simple linear regression analysis demonstrated that endothelial function significantly correlated with left ventricular mass index and 2-hour blood glucose in 75-g oral glucose tolerance test, but not with fasting blood glucose. Multiple linear regression analysis revealed that endothelial function significantly correlated with 2-hour blood glucose (beta=-2.68, P<0.05) after we controlled for other clinical variables. Patients were divided into 3 groups according to 2-hour blood glucose levels. Endothelial function was more impaired in patients with diabetes (n=12; 4.7+/-1.8%) and in those with impaired glucose tolerance (n=31; 6.3+/-2.9%) than in those with normal glucose tolerance (n=64; 8.4+/-4.5%) (P<0.05), but left ventricular mass index was similar in these 3 groups. Abnormal glucose tolerance assessed by 75-g oral glucose tolerance test, rather than left ventricular hypertrophy, may have direct pathophysiological relevance to endothelial dysfunction in borderline to moderate hypertensive patients.


Assuntos
Endotélio Vascular/fisiopatologia , Intolerância à Glucose/fisiopatologia , Hipertensão/fisiopatologia , Adulto , Fatores Etários , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Artéria Braquial/fisiopatologia , Colesterol/sangue , Feminino , Teste de Tolerância a Glucose , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Humanos , Hipertensão/sangue , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Análise de Regressão , Fumar , Triglicerídeos/sangue
7.
Atherosclerosis ; 147(1): 69-75, 1999 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-10525127

RESUMO

Our aim was to assess the potential role of lipoxygenase (LO) products in neointimal formation following vascular injury. We investigated the effect of LO pathway inhibition, by phenidone, on the concentration of 12- and 5-hydroxyeicosatetraenoic acid (12- and 5-HETE) in rat whole blood and in aortic tissue. We also examined the effect of phenidone on myoneointimal formation in balloon-injured rat carotid arteries. Phenidone significantly decreases the concentration of HETEs in aortic tissue, and decreases neointimal size even though there is no difference in the BrdU index. These data indicate that the LO product participates in developing neointima following balloon-induced vascular injury, and that the LO blocker phenidone decreases neointimal size possibly by suppressing migration of smooth muscle cells.


Assuntos
Lesões das Artérias Carótidas/patologia , Inibidores de Lipoxigenase/farmacologia , Lipoxigenase/fisiologia , Túnica Íntima/patologia , Ácido 12-Hidroxi-5,8,10,14-Eicosatetraenoico/metabolismo , Angioplastia com Balão/efeitos adversos , Animais , Aorta Torácica/lesões , Aorta Torácica/metabolismo , Aorta Torácica/patologia , Lesões das Artérias Carótidas/etiologia , Divisão Celular , Ácidos Hidroxieicosatetraenoicos/metabolismo , Masculino , Pirazóis/farmacologia , Ratos , Ratos Sprague-Dawley
8.
J Hypertens ; 14(10): 1223-8, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8906522

RESUMO

OBJECTIVE: This study was designed and conducted to assess the clinical significance of left ventricular geometric patterns and physical fitness in subjects with untreated borderline and mild hypertension. METHODS: Symptom-limited maximal treadmill stress testings and echocardiographic examinations were administered to 192 previously unmedicated men. Left ventricular geometric patterns were determined by the combined criteria of left ventricular mass index and relative wall thickness. Subjects whose left ventricular mass index was < 125 g/m2 were followed up for more than 3 years. RESULTS: Normalized treadmill time was lower and pressure rate products at peak exercise were higher in patients with concentric hypertrophy than in those with normal geometry. Of the 77 patients who revealed left ventricular mass index at baseline < 125 g/m2 and who were successfully followed without medication for more than 3 years, 18 demonstrated concentric hypertrophy at the final follow-up examination. During the follow-up period, these 18 patients had significant further augmentation of concentric geometric features, significant decreases in both cardiac output and normalized treadmill time, and significant increases in casual blood pressure and total peripheral resistance compared with those at baseline. CONCLUSION: Patients with concentric hypertrophy exhibited slightly but significantly impaired levels of physical fitness and cardiac work efficiency, and the progression of concentric hypertrophy demonstrated further impairments of these conditions. Therefore, not only lowering blood pressure, but also improving left ventricular hypertrophy, cardiovascular hemodynamics, and physical fitness might be required in patients with concentric hypertrophy.


Assuntos
Tolerância ao Exercício , Hipertensão/fisiopatologia , Função Ventricular Esquerda , Adulto , Ecocardiografia , Seguimentos , Humanos , Hipertensão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Aptidão Física , Estudos Prospectivos , Análise de Regressão , Volume Sistólico
9.
Am J Hypertens ; 10(6): 587-91, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9194503

RESUMO

The relationship of the hyperinsulinemic state to left ventricular hypertrophy, left ventricular geometric patterns, microalbuminuria, and physical fitness were studied in 52 middle-aged unmedicated men with borderline and mild hypertension. Left ventricular mass index and relative wall thickness were assessed by echocardiography. Physical fitness was determined by symptom-limited maximal treadmill stress testings. The urinary concentration of microalbumin and C-peptide was measured in 24-h urine samples by radioimmunoassey. The 24-h urinary C-peptide excretion rate was correlated with left ventricular mass index (r = 0.46), relative wall thickness (r = 0.41), treadmill time (r = -0.35), normalized treadmill time (r = -0.52), systolic blood pressure at peak exercise (r = 0.29), and 24-h urinary microalbumin excretion (r = 0.48). Stepwise multiple regression analysis identified the left ventricular mass index, the 24-h urinary albumin excretion, and the normalized treadmill time as variables in the equation for the 24-h urinary C-peptide excretion. Thus, the hyperinsulinemic state is related to left ventricular hypertrophy, microalbuminuria, and impaired physical fitness in patients with borderline and mild hypertension.


Assuntos
Albuminúria/fisiopatologia , Hiperinsulinismo/fisiopatologia , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Aptidão Física , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
10.
Am J Hypertens ; 11(3 Pt 1): 286-92, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9544868

RESUMO

To investigate whether QT dispersion increases in borderline and mild hypertension during a longitudinal observation of > 3 years and whether it is improved with medications, left ventricular geometric patterns and QT dispersion were studied with special regard to their longitudinal changes in 85 male borderline and mild hypertensive subjects with left ventricular mass index < 125 g/m2. These subjects were followed for > 3 years without medication. Thirty-two patients with a left ventricular mass index > 125 g/m2 at the end of follow-up period were further observed using antihypertensive drugs for an additional 3 years. Echocardiograms and electrocardiograms were obtained at the beginning and end of the follow-up period. At the end of the follow-up period, subjects were classified into four groups based on ventricular geometric patterns determined by left ventricular mass index and relative wall thickness in diastole. The QT dispersion was greater in patients with concentric hypertrophy (56+/-18 msec) than in patients with normal geometry (41+/-17 msec) (P < .05) and increased significantly in the former group during the follow-up period. After medication, the left ventricular mass index regressed and the QT dispersion decreased (from 55+/-21 to 50+/-26 msec, P < .01) in these patients. Thus, these findings suggest that changes in the QT dispersion reflect both concentric evolution and regression of left ventricular hypertrophy.


Assuntos
Ecocardiografia , Eletrocardiografia , Hipertensão/diagnóstico por imagem , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/fisiopatologia , Adulto , Pressão Sanguínea/fisiologia , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Estudos Retrospectivos
11.
Metabolism ; 47(5): 493-6, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9591736

RESUMO

We investigated the possibility of variations in the genetic transmission of insulin sensitivity in the offspring of spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKYs) obtained from different sources (Charles River, Tokyo, Japan [NCrj]; and Funabashi Farm, Chiba, Japan [Izm]) with the insulin suppression test (IST) using a somatostatin analog, glucose, and insulin. The steady-state blood glucose (SSBG) in the IST and the glucose infusion required (GIR) in the euglycemic-hyperinsulinemic clamp differ significantly between obese and lean Zucker rats, indicating that both methods are useful for identifying insulin resistance. The fasting blood glucose and SSBG of the IST were significantly higher in SHR/Izm than in WKY/Izm. We did not observe a significant difference between SHR/NCrj and WKY/NCrj. These results indicate that the genetic transmission of hypertension and impaired insulin sensitivity may be variable and that insulin resistance does not play an important role in the pathogenesis of hypertension in the SHR.


Assuntos
Hipertensão/genética , Resistência à Insulina/genética , Animais , Glicemia/metabolismo , Pressão Sanguínea/genética , Pressão Sanguínea/fisiologia , Peso Corporal/genética , Peso Corporal/fisiologia , Jejum , Frequência Cardíaca/genética , Frequência Cardíaca/fisiologia , Insulina/sangue , Antagonistas da Insulina , Masculino , Obesidade/sangue , Obesidade/genética , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Ratos Zucker
12.
Hypertens Res ; 20(2): 105-11, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9220274

RESUMO

This study was conducted to investigate the effects of long-term administration of a calcium-channel antagonist (nifedipine) and a beta-blocker (acebutolol) on physical fitness in men with mild hypertension. All subjects underwent symptom-limited treadmill stress testing and routine echocardiographic studies. Twenty-two subjects who had either a causal diastolic blood pressure of more than 105 mmHg or a left ventricular mass index (LVMI) of 125 g/m2 or more during follow-up were assigned to receive medical therapy. The other 31 men who did not meet either criterion were continuously followed-up without medication. Among the 22 treated men, the age-adjusted treadmill time (normalized treadmill time, TMTn) significantly decreased before the initiation of medication, while 31 untreated men showed no change in TMTn throughout the study. The 22 treated subjects were subsequently divided into two groups; 13 were given nifedipine and 9 were given acebutolol. All treated subjects were followed-up for more than 3 years. After treatment, the two groups showed similar reductions in blood pressure and LVMI, but a different outcome for TMTn: TMTn increased from 104 +/- 8% to 115 +/- 16% in subjects given nifedipine (p < 0.05) and decreased from 106 +/- 12% to 99 +/- 10% (p < 0.01) in those given acebutolol. Thus, the physical fitness of subjects who required medication significantly deteriorated without medication; their physical fitness improved after treatment with a calcium-channel antagonist and deteriorated after treatment with a beta-blocker.


Assuntos
Acebutolol/uso terapêutico , Antagonistas Adrenérgicos beta/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Hipertensão/tratamento farmacológico , Nifedipino/uso terapêutico , Aptidão Física , Acebutolol/efeitos adversos , Antagonistas Adrenérgicos beta/efeitos adversos , Adulto , Pressão Sanguínea/efeitos dos fármacos , Quimioterapia Combinada , Ecocardiografia , Humanos , Assistência de Longa Duração , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Função Ventricular Esquerda
13.
Eur J Pharmacol ; 411(1-2): 155-160, 2001 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-11137870

RESUMO

We tested the hypothesis that relaxation of the rat mesenteric artery in response to insulin is mediated by K(+) channels. Two concentrations of insulin (10 and 100 mU/ml) induced relaxation of the artery by 6+/-1%, 24+/-3% (mean+/-S.E.M.). Denudation of the endothelium or precontraction by KCl (30 mM), clotrimazole (10 microM), a cytochrome P450 inhibitor, charybdotoxin (30 nM) an inhibitor of large-conductance Ca(2+)-activated K(+) channels, abolished the relaxation of the artery in response to insulin. However, N(omega)-nitro-L-arginine methyl ester (L-NAME; 100 microM), an inhibitor of nitric oxide synthase, apamin (1 microM), an inhibitor of small-conductance Ca(2+)-activated K(+) channels, or glibenclamide (10 microM), an ATP-sensitive K(+) channels blocker, did not attenuate the relaxation of the artery caused by insulin. These results suggest that the relaxation of rat mesenteric artery in response to insulin is mediated mostly by large-conductance Ca(2+)-activated K(+) channels, perhaps an endothelium-derived hyperpolarizing factor (EDHF).


Assuntos
Insulina/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Canais de Potássio/fisiologia , Vasodilatação/efeitos dos fármacos , Animais , Apamina/farmacologia , Charibdotoxina/farmacologia , Clotrimazol/farmacologia , Relação Dose-Resposta a Droga , Endotélio Vascular/fisiologia , Glibureto/farmacologia , Técnicas In Vitro , Masculino , Artérias Mesentéricas/fisiologia , NG-Nitroarginina Metil Éster/farmacologia , Fenilefrina/farmacologia , Bloqueadores dos Canais de Potássio , Ratos , Ratos Sprague-Dawley , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologia
14.
Nihon Jinzo Gakkai Shi ; 40(4): 240-4, 1998 May.
Artigo em Japonês | MEDLINE | ID: mdl-9654906

RESUMO

Since insulin resistance and/or hyperinsulinemia may contribute to structural changes of the vascular wall, the influence of antihypertensive agents on insulin sensitivity could interfere with the long term outcome of blood pressure reduction. Although it is postulated that increased peripheral circulation due to vasodilating agents improves insulin sensitivity, reflex sympathetic activation elicited by blood pressure reduction may influence insulin sensitivity. Thus we investigated the different effects of an alpha blocker (doxazosin) as well as a direct vasodilation (hydralazine) on insulin sensitivity and on sympathetic function in spontaneously hypertensive rats (SHR). Doxazosin and hydralazine decreased mean arterial pressure to a similar extent. Doxazosin, but not hydralazine decreased steady state blood glucose. Plasma norepinephrine increased in doxazosin and hydralazine treated groups as compared to the control group. Thus, despite their similar effects on blood pressure and plasma norepinephrine, alpha-1 blocker improved insulin sensitivity while the direct vasodilator failed to do so, and this difference is probably related to blockade of the alpha-1 receptor rather than to peripheral vasodilation.


Assuntos
Antagonistas Adrenérgicos alfa/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Doxazossina/uso terapêutico , Hidralazina/uso terapêutico , Hipertensão/tratamento farmacológico , Resistência à Insulina , Sistema Nervoso Simpático/efeitos dos fármacos , Simpatolíticos/uso terapêutico , Vasodilatadores/uso terapêutico , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Anti-Hipertensivos/farmacologia , Doxazossina/farmacologia , Hidralazina/farmacologia , Hipertensão/fisiopatologia , Masculino , Ratos , Ratos Endogâmicos SHR , Simpatolíticos/farmacologia , Vasodilatadores/farmacologia
15.
Nihon Jinzo Gakkai Shi ; 34(6): 717-23, 1992 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-1336077

RESUMO

Endothelium-derived relaxing factor (EDRF) is a substance that is released by the vascular endothelium and mediates vasodilator responses induced by various substances including acetylcholine (AC). Superoxide anion (O2-) inactivates EDRF. It is well known that the endothelium-dependent vascular relaxations to AC are depressed in the aorta of spontaneously hypertensive rats (SHR). We studied the role of O2- on onset and maintenance of hypertension in SHR. Male 4- and 17-week old SHR (4SHR, 17SHR), and enalapril treated 17-week old SHR (5 mg/kg/day for 4 weeks: ETSHR), and age-matched normotensive Wistar-Kyoto rats (WKY; 4WKY, 17WKY) were used. Relaxation responses to AC or superoxide dismutase (SOD) were measured in isolated aortae from rats. Mean arterial pressure (MAP) was measured after injection of SOD in rats under conscious state. Systolic blood pressure of 4SHR, 17SHR, ETSHR, 4WKY, and 17WKY were 129 +/- 2 mmHg, 203 +/- 3 mmHg, 158 +/- 3 mmHg, 97 +/- 1 mmHg, and 138 +/- 2 mmHg, respectively. Although relaxation responses to AC were decreased in aortae from 4SHR, 17SHR, and ETSHR compared with those from age-matched WKY, relaxation responses to SOD dit not differ between SHR and corresponding WKY. Whereas the injection of SOD(10000 U/kg) elicited a significant reduction of MAP in 4SHR (-11 +/- 3 mmHg) and 17SHR (-24 +/- 5 mmHg), it has no effect in WKY. These data suggest that AC mediated endothelium-dependent relaxation is attenuated in SHR and that excessive O2- in the endothelium resulted from hypertension may contributes the decreased response in SHR.


Assuntos
Hipertensão/etiologia , Superóxidos , Vasodilatação/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Ânions , Pressão Sanguínea/efeitos dos fármacos , Técnicas In Vitro , Masculino , Óxido Nítrico/fisiologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Superóxido Dismutase/farmacologia , Superóxidos/metabolismo
16.
Nihon Jinzo Gakkai Shi ; 41(7): 685-91, 1999 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-10572393

RESUMO

Endothelium-derived hyperpolarizing factor (EDHF) as a factor in blood pressure regulation has received attention recently. However, its role in insulin-induced vasodilation is not clear. We investigated the mechanism of vasodilation induced by insulin in vitro using mesenteric arteries isolated from normotensive rats. The 2nd branch of the mesenteric artery was isolated from male Sprague-Dawley rats (12-14 weeks old), mounted on microcannules in a chamber and perfused with Krebs solution. The diameter of this segment was measured continuously with a video system under the following conditions: intraluminal insulin administration (10 and 100 mU/ml) with and without pretreatment by denudation, N omega-methyl-L-arginine methyl ester (L-NAME), indomethacin, tetrabuthylammonium (TBA, non-specific Ca2+ activated K channel blocker), charybdotoxin (ChTx, large-conductance Ca2+ activated K channel blocker), apaminn (small-conductance Ca2+ activated K channel blocker) or Na+/k(+)-ATPase blocker (ouabain). Insulin treatment induced dose-dependent vasodilation. The effects of insulin were significantly suppressed by denudation, TBA, apamin, and ChTx. L-NAME, indomethacin and ouabain did not influence the insulin-induced vasodilation. Results suggested that insulin dilates small arteries by activating the Ca2+ activated K channel.


Assuntos
Fatores Biológicos/fisiologia , Insulina/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Animais , Fatores Biológicos/metabolismo , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Técnicas In Vitro , Masculino , Canais de Potássio/metabolismo , Ratos , Ratos Sprague-Dawley
17.
Nihon Jinzo Gakkai Shi ; 41(7): 692-6, 1999 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-10572394

RESUMO

Although angiotensin AT1 receptor antagonist(AT1 A) improves insulin sensitivity in insulin resistant models, its effect on spontaneously hypertensive rats(SHR) has not been elucidated. We investigated the effects of AT1 A, candesartan on insulin sensitivity in SHR/Izm and the role of sympathetic activity in its mechanism. In 9-week-old SHR/Izm, candesartan(10 mg/kg/day) was given orally for 5 days. A control group received vehicle. On the 6th day, mean arterial pressure (MAP), heart rate(HR), plasma norepinephrine (PNE), plasma epinephrine(PE) and plasma dopaminc(PDA) were measured in both groups (n = 11 in each group). In the separate groups of rats, fasting blood glucose (FBG), serum sodium, serum potassium and insulin sensitivity by steady state blood glucose (SSBG) were assessed (n = 16 in the Candesartan group and n = 8 in the Control group). MAP and SSBG were significantly lower in the Candesartan group (117 +/- 2 mmHg and 138 +/- 5 mg/dl) than those in the Control group(155 +/- 6 mmHg and 164 +/- 10 mg/dl). Body weight, HR, FBG, PNE, PE, PDA, sodium and potassium were the same between the groups. In conclusion, since AT1 A, candesartal lowers blood pressure and improves insulin sensitivity irrespective of sympathetic activity in SHR/Izm, it is useful in treating hypertension associated with insulin resistance.


Assuntos
Antagonistas de Receptores de Angiotensina , Anti-Hipertensivos/uso terapêutico , Benzimidazóis/uso terapêutico , Hipertensão/tratamento farmacológico , Insulina/metabolismo , Sistema Nervoso Simpático/fisiopatologia , Tetrazóis/uso terapêutico , Animais , Anti-Hipertensivos/farmacologia , Benzimidazóis/farmacologia , Compostos de Bifenilo , Pressão Sanguínea , Modelos Animais de Doenças , Hipertensão/fisiopatologia , Resistência à Insulina , Masculino , Ratos , Ratos Endogâmicos SHR , Tetrazóis/farmacologia
18.
Nihon Jinzo Gakkai Shi ; 42(8): 619-24, 2000 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-11195397

RESUMO

Previous studies have shown that hypertension causes endothelial dysfunction. To study the influence of exogenous nitric oxide(NO) on endothelial dysfunction produced by hypertension, we administered a non-depressor dose of nipradilol to two-kidney, one-clip renovascular hypertensive rats(2K1C). Sprague-Dawley rats underwent either sham surgery(G-1) or clipping of the left renal artery. From day seven, 2K1C were randomized into 3 groups, placebo treatment(G-2), nipradilol treatment(G-3,) and propranolol treatment(G-4). Urinary NO2- + NO3-(NOx) excretion (UNOx V) was measured 4 weeks after clipping, and then, acetylcholine(Ach), A23187, or sodium nitroprusside(SNP)-induced relaxation were measured in the aorta. Blood pressure was increased in G-2, G-3, and G-4 compared to G-1. UNOx V was lower in G-2, G-3, and G-4 compared to G-1, but UNOx V was higher in G-3 compared to G-2 and G-4. Although Ach or A23187-induced relaxation was significantly decreased in isolated artery from G-2, G-3, and G-4 compared with those from G-1. Ach- or A23187-induced relaxation was improved in G-3. SNP-induced relaxation did not differ among the 4 groups. These results suggest that exogenous NO from nipradilol reduces the endothelial dysfunction caused by hypertension without changing the blood pressure.


Assuntos
Endotélio Vascular/fisiopatologia , Hipertensão Renovascular/fisiopatologia , Doadores de Óxido Nítrico/farmacologia , Propanolaminas/farmacologia , Acetilcolina/farmacologia , Animais , Pressão Sanguínea , Calcimicina/farmacologia , Modelos Animais de Doenças , Hipertensão Renovascular/tratamento farmacológico , Técnicas In Vitro , Masculino , Óxido Nítrico/urina , Doadores de Óxido Nítrico/uso terapêutico , Propanolaminas/uso terapêutico , Ratos , Ratos Wistar , Vasodilatação/efeitos dos fármacos
19.
Nihon Jinzo Gakkai Shi ; 38(12): 625-33, 1996 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-9014483

RESUMO

Antihypertensive effects of beni-koji were studied using 29 outpatients with mild hypertension in a placebo-controlled double-blind comparative fashion. After a 4-week vehicle (apple juice) run-in period, 13 patients were assigned to receive beni-koji aqueous extracts containing juice once daily (27 g of beni-koji eq. per day) for 8 weeks and 16 were assigned to vehicle. Two patients assigned to the vehicle group did not complete the study. In addition to casual blood pressure, 24-hr non-invasive ambulatory blood pressure (ABP) was monitored in 6 patients given the beni-koji drink and 5 patients given the vehicle. 1) In the beni-koji group, both casual systolic and diastolic pressure decreased significantly during the treatment period (from 150 +/- 10/96 +/- 6 mmHg to 140 +/- 10/89 +/- 10 mmHg, p < 0.01). The averages of the 24-hr blood pressure recorded in ABP (24-BP) also significantly decreased (from 141 +/- 17/95 +/- 13 mmHg to 132 +/- 21/86 +/- 10 mmHg, p < 0.05) when compared with those of the control period. Casual pressure normalized (less than 140/90 mmHg) in 4 patients who received beni-koji. Circadian variation of the blood pressure by ABP showed a significant decrease during the daytime. 2) In the vehicle group, casual systolic pressure did not change significantly (from 155 +/- 8 mmHg to 151 +/- 12 mmHg), but diastolic pressure decreased significantly (98 +/- 7 mmHg to 93 +/- 6 mmHg). Casual blood pressure did not normalize in any of the patients and 24-BP did not change significantly. 3) Summative evaluation of safety showed that no problems appeared in the beni-koji group. In conclusion, beni-koji appears to be an effective and safe food material for mild essential hypertension. The mechanism of the antihypertensive effect of beni-koji still remains to be investigated.


Assuntos
Anti-Hipertensivos , Aspergillus , Hipertensão/terapia , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
J Hypertens Suppl ; 6(4): S91-3, 1988 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2977181

RESUMO

To investigate the predictive value of exercise tests and diastolic function measurements for the progression of left ventricular hypertrophy, symptom-limited treadmill stress testing and echocardiography were performed before and after a follow-up period of 3.5 years in 47 mild hypertensive men aged 42 +/- 2 years. The men were classified into three groups by the progression of the left ventricular mass index (%LVMI) during the observation, i.e. (LVMI after follow-up) - (LVMI before follow-up)/(LVMI before follow-up). The high-progression group (n = 13) had a %LVMI exceeding mean +/- 2/3s.d. of all subjects; the low-progression group (n = 21) had a %LVMI within mean +/- 2/3s.d. and the non-progression group (n = 13) had a %LVMI less than mean -2/3s.d. At the beginning of the observation, age, blood pressure at rest, LVMI, ejection fraction, mean velocity of circumferential fibre shortening, peak shortening rate and systolic time intervals (ET/PEP, ratio of ejection time to pre-ejection period) were similar among the three groups. However, the high-progression group showed a higher systolic pressure at peak exercise, a lower peak filling rate and a longer time to peak filling rate (TPFR) as corrected by the R-R interval of the ECG. These data suggest that systolic pressure at peak exercise and echocardiographically assessed diastolic function are useful in predicting the progression of cardiac involvement in mild hypertension.


Assuntos
Cardiomegalia/patologia , Hipertensão/patologia , Adulto , Seguimentos , Hemodinâmica , Humanos , Pessoa de Meia-Idade , Prognóstico
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