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PubMed2005

Attenuation of exaggerated exercise blood pressure response in African-American women by regular aerobic physical activity.

INTRODUCTION: A hyperreactive blood pressure response to exercise is a predictor of developing hypertension. The present study determined the influence of physical activity on an exaggerated exercise blood pressure response (EEBPR) in normotensive African-American women. METHODS: We screened 36 women 18-26 years of age for EEBPR defined as a > or = 50 mm Hg difference in systolic blood pressure at rest and during exercise at 50% peak oxygen uptake (VO2peak). Seven subjects demonstrated an EEBPR and participated in the study. Study participants trained for eight weeks on a bicycle ergometer at a work intensity of 70% VO2peak. Blood pressure, heart rate, cardiac output (CO), stroke volume (SV), and total peripheral vascular resistance (TPR) were determined at baseline and during submaximal exercise at power outputs of 30 W and 50% VO2peak. Subjects served as their own controls, and data were evaluated by using a paired t test at P<.05. RESULTS: Effectiveness of the intervention was shown by a significantly greater VO2peak associated with significant decrements in systolic and mean arterial pressures at power outputs of 30 W and 50% VO2peak. A significant decrement in heart rate was observed during exercise at 30 W. Significant increments in CO and SV and decrement in TPR were found during exercise at 50% VO2peak. CONCLUSION: The reduction in TPR associated with regular aerobic physical activity may attenuate the EEBPR and decrease the risk for hypertension in normotensive, young-adult, African-American women.

Adolescent↗

PubMed2006

The thromboxane receptor antagonist S18886 attenuates renal oxidant stress and proteinuria in diabetic apolipoprotein E-deficient mice.

Arachidonic acid metabolites, some of which may activate thromboxane A(2) receptors (TPr) and contribute to the development of diabetes complications, including nephropathy, are elevated in diabetes. This study determined the effect of blocking TPr with S18886 or inhibiting cyclooxygenase with aspirin on oxidative stress and the early stages of nephropathy in streptozotocin-induced diabetic apolipoprotein E(-/-) mice. Diabetic mice were treated with S18886 (5 mg . kg(-1) . day(-1)) or aspirin (30 mg . kg(-1) . day(-1)) for 6 weeks. Neither S18886 nor aspirin affected hyperglycemia or hypercholesterolemia. There was intense immunohistochemical staining for nitrotyrosine in diabetic mouse kidney. In addition, a decrease in manganese superoxide dismutase (MnSOD) activity was associated with an increase in MnSOD tyrosine-34 nitration. Tyrosine nitration was significantly reduced by S18886 but not by aspirin. Staining for the NADPH oxidase subunit p47(phox), inducible nitric oxide synthase, and 12-lipoxygenase was increased in diabetic mouse kidney, as were urine levels of 12-hydroxyeicosatetraenoic acid and 8-iso-prostaglandin F(2alpha). S18886 attenuated all of these markers of oxidant stress and inflammation. Furthermore, S18886 significantly attenuated microalbuminuria in diabetic mice and ameliorated histological evidence of diabetic nephropathy, including transforming growth factor-beta and extracellular matrix expression. Thus, in contrast to inhibiting cyclooxygenase, blockade of TPr may have therapeutic potential in diabetic nephropathy, in part by attenuating oxidative stress.

Animals↗

PubMedDate not supplied

Cardiovascular function of African women with different BMIs and blood pressures: the POWIRS study.

INTRODUCTION: The aim of this study was to investigate the cardiovascular profiles of a group of African women with different body mass indices and blood pressures. MATERIALS AND METHODS: The study included a sample of 98 apparently healthy African women. The subjects were divided into three groups: lean normotensive (lean NT), overweight/obese normotensive (OW/OB NT), and overweight/obese hypertensive (OW/OB HT). The Finometer apparatus was used to obtain a more elaborate cardiovascular profile. The lipid profile and subcutaneous fat distributions were also determined. RESULTS: A positive correlation between blood pressure and increased adiposity was obtained. Cardiac output (CO) was elevated in both OW/OB groups. Arterial compliance (CW) was significantly decreased and total peripheral resistance (TPR) significantly increased in the OW/OB HT group compared to the OW/OB NT group. In the total group, systolic and diastolic blood pressure could be explained best by the abdominal skinfold, which showed a direct positive association with TPR and a negative association with CW . In the OW/OB HT group, the increased TPR could best be explained by the abdominal skinfold. CONCLUSIONS: In the OW/OB HT group, an increase in CO and decrease in vascular function led to the hypertensivity of this group. This seems to be related to a truncal, especially abdominal subcutaneous fat distribution. The decreased vascular function was reaffirmed by the pulse pressure (PP) exceeding 63 mmHg, indicating that this group was at high risk for the development of further cardiovascular complications. Lack of significant differences between the OW/OB groups for the anthropometric and lipid profile variables and the difference in age may indicate that the younger OW/OB NT group was at high risk and should be followed up in ensuing years.

Adult↗

PubMed2006

Left ventricular mass in patients with hyperthyroidism.

BACKGROUND: The mechanisms of increased left ventricular mass (LVM) in hyperthyroidism are complex. The aim was to determine the effects of hyperthyroidism and thyreostatic therapy on LVM regarding its interrelationship with factors responsible for the heart's hemodynamic workload. MATERIAL/METHODS: The study included 51 hyperthyroid subjects and 30 healthy controls. Left heart ventricle parameters evaluated using standard ultrasonocardiography were: left ventricular volume (end-systolic and end-diastolic), left ventricle posterior wall thickness at systole (LVPWs) and diastole (LVPWd) with the respective interventricular septal thicknesses (IVSs, IVSd), LVM, stroke volume (SV), cardiac output (CO), output-pressure index (OPI), and total peripheral resistance (TPR). Systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), and body mass index (BMI) were investigated. Measurements were repeated after two weeks of thiamazole treatment and after attaining euthyreosis. RESULTS: Compared with controls, the hyperthyroid subjects had significant thickening of LVPWd, LVPWs, and IVSs, increased LVM, augmented SV, CO, OPI, SBP, and HR, but reduced TPR and DBP. Hyperthyroid treatment did not normalize LVM. LVM showed positive correlations with SV, CO, OPI, SBP, BMI, and serum triiodothyronine concentration and negative correlation with TPR. In multivariate regression analysis, LVM correlated with SBP, SV, and BMI (R=0.64, p<0.001). CONCLUSIONS: 1) In hyperthyroid patients, LVM is increased, mainly due to its eccentric remodeling, probably caused by volume overload; the increased LVM does not seem to be reversible despite attainment of euthyreosis. 2) The increased LVM is probably related to the heart's hemodynamic workload and reflects adaptive changes.

Adult↗

PubMed1991

Inhibition of human platelet aggregation by endothelium-derived relaxing factor, sodium nitroprusside or iloprost is potentiated by captopril and reduced thiols.

We have examined whether inhibitors of angiotensin-converting enzyme-containing sulfhydryl groups such as, captopril (CPT) or SQ 14,534, the nonsulfhydryl-containing angiotensin-converting enzyme inhibitors, teprotide (TPR) or enalaprilat (ENA) and other structurally unrelated sulfhydryl-containing compounds, N-2-mercaptopropionylglycine (MPG) or N-acetyl-L-cysteine (NAC), could influence platelet aggregation. Incubation of human washed platelets with CPT, SQ 14,534, TPR, ENA, MPG or NAC (0.1-0.5 mM) did not modify their aggregatory responses to thrombin. However, the antiaggregatory properties of endothelial cells cultured from bovine aorta were potentiated by CPT, SQ 14,534, MPG or NAC but not by TPR or ENA (40-100 microM). CPT (100-500 microM) or NAC (50-200 microM) but not ENA (100 and 500 microM) also potentiated the antiaggregatory effects of sodium nitroprusside (1.0 microM) or iloprost (0.2 nM). The ability of the thiol-containing compounds (CPT or NAC) to potentiate the antiaggregatory effects of sodium nitroprusside or iloprost was not associated with an elevation of platelet cyclic GMP or cyclic AMP levels, respectively. Thus, CPT and other sulfhydryl-containing compounds can synergize with antiplatelet compounds, thereby enhancing the ability of endothelial-derived autocoids to inhibit platelet aggregation. The mechanism responsible for this potentiating effect of thiols on platelet aggregation is not known, but may relate to the ability of thiol-containing compounds to act as intracellular scavengers of oxygen-derived free radicals.

Acetylcysteine↗

PubMedDate not supplied

Univentricular support results in reduction of pulmonary resistance and improved right ventricular function.

A retrospective analysis was performed to assess the effects of univentricular support on the transpulmonary gradient (TPG), pulmonary vascular resistance (PVR), total pulmonary resistance (TPR), and right ventricular ejection fraction (RVEF) in 16 patients who spent from 2 to 144 days (mean, 61) on the Novacor left ventricular assist system ([LVAS] Novacor Corp., Baxter Healthcare, Oakland, CA) as a bridge to cardiac transplantation. Results revealed a significant reduction in the TPR, and improvement in RVEF while patients were on the LVAS. After orthotopic heart transplantation (OHTx), TPG and PVR were significantly lower than when calculated before support. It was concluded, therefore, that the reduction in the TPR and the improvement in the RVEF, seen in patients who were provided univentricular support with the Novacor LVAS, are associated with a significant reduction in the TPG and the PVR, which are persistent after OHTx. Four patients who otherwise would have been considered at higher risk for OHTx because of elevated pulmonary resistance before veniventricular support underwent successful OHTx after LVAS support.

Adolescent↗

PubMed1990

[Quantitative evaluation of right ventricular overload in cor pulmonale using 201T1 myocardial SPECT].

In patients with right ventricular overload, the free wall of the right ventricle is often visualized by 201T1 myocardial scintigraphy. To determine quantitatively the discriminant and characteristics of cor pulmonale, 201T1 myocardial perfusion single photon emission computed tomography (SPECT) was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and seven with restrictive pulmonary disease (RPD). We selected one section of the short-axis image of SPECT in which the right ventricle was most clearly visualized, and defined the T1-score as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid and posterior regions of the right ventricular free wall to the sum of counts in the ROI at the posterior, lateral, anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. Correlation of the T1-score with mean pulmonary arterial pressure (mPAP), systolic pulmonary arterial pressure (sPAP), and total pulmonary vascular resistance (TPR), as obtained by right cardiac catheterization, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) were evaluated. The results were as follows: 1. In the patients with COPD, the T1-score correlated positively with mPAP (r = 0.71, p less than 0.005), TPR ( r = 0.69, p less than 0.005), and PaCO2 (r = 0.63, p less than 0.01), and it correlated inversely with PaO2 (r = -0.58, p less than 0.05). However, there was no significant correlation between the T1-score and mPAP, TPR, PaCO2, and PaO2 in the patients with RPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1989

Specific features of left ventricular hypertrophy in hypertensive obese women. An echocardiographic study.

The echocardiographic features of the left ventricle of 37 obese women (body mass index above 30) and 37 lean controls, matched for sex, age, height and blood pressure levels, were studied. Twenty-six patients in each group were hypertensive. The normotensive obese patients did not show any differences, comparing to the normotensive controls; on the contrary, the hypertensive obese patients had higher left ventricular mass (LVM), stroke volume and cardiac output (CO), and lower total peripheral resistance (TPR) than the hypertensive controls. A positive correlation was found between the LVM and the CO (r = 0.57, P less than 0.01) in hypertensive obese patients, and between the relative wall thickenss (h/r, that is the ratio between the left ventricular wall thickness and the left ventricular radius) and TPR (r = 0.64, P less than 0.01) in the hypertensive controls. It is concluded that obesity per se does not determine left ventricular hypertrophy in women; however, when obesity is associated with arterial hypertension, a distinct pattern of hypertrophy, characterized by high CO and low TPR, develops.

Adult↗

PubMed1989

[Use of prazosin and capoten in the treatment of heart failure in patients with ischemic heart disease].

Eighty eight patients with ischemic heart disease were studied. There was a significant increase in pulmonary blood flow time (Tp), pulmonary blood volume (BVp). mean pulmonary pressure (MPP), and total pulmonary resistance (TPR). as regarded as initial signs of heart failure, in group 1 that comprised 35 patients out of 65 after a graded isometric loading test. After prazosin therapy, these patients showed a significant decrease in blood pressure, only moderate reduction in MPP and TPR, and a rise of the cardiac index (CI). There was a significant decrease in Tp, BVp, MPP, TPR during the loading test following the therapy. From group 2, 23 patients were treated with capoten. The monotherapy was beneficial in 9 patients, capoten was discontinued in 1 case; 13 patients received a combined therapy with glycosides and saluretics. In all the cases, a positive clinical and hemodynamic effect (lower blood pressure, total peripheral resistance, BVp, higher CI with virtually unchanged heart rate) was achieved.

Adult↗

PubMed1989

Experimental paratuberculosis (Johne's disease)--studies on biochemical parameters in cattle.

Ten male Holstein-Friesian calves naturally infected by Mycobacterium paratuberculosis were experimentally re-infected orally at an average of 17 days. Monthly measurements were conduced of the following activities, in the period between post infection days 160 and 400: total protein (TPR), albumin (ALB), cholesterol (CHOL), triglycerides (TRIG), Zn and Cu concentrations as well as sorbitol dehydrogenase, lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (alpha-HBDH), gamma-glutamyltransferase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), alkaline phosphatase and fructose-1,6-diphosphate aldolase (ALD). TPR, ALB, TRIG, and CHOL were reduced by day 400, in conjunction with disorders of digestion and absorption. Increased activities of CK, ALD, LDH, alpha-HBDH, AST and ALT primarily indicated damage to skeletal muscle and/or liver. Serum CK and ALD activities as well as TRIG and TPR concentrations may serve as aids to specific diagnosis of paratuberculosis, particularly in the advanced stage of the disease.

Animals↗

PubMedDate not supplied

[Assessment of the state of pulmonary circulation in infants of the 1st year of life with complete transposition of great vessels and ventricular septal defects].

The condition of pulmonary circulation in children of the first year of life with complete transposition of the great vessels (CTGV) and interventricular septal defect (IVSD) was evaluated by comparing the complex of hemodynamic and angiometric values obtained in catheterization of the heart cavities and angiocardiography. All patients were divided into two hemodynamic groups according to the blood flow in the lungs: group 1 - with the ratio of pulmonary to systemic circulation (PC/SC) greater than 1; group 2 - with the PC/SC ratio less than 1. In group 1 patients the ratio of effective pulmonary circulation (EC) to PC is always less than the ratio of EC to SC both in normal and in increased total pulmonary resistance (TPR); in group 2 patients, in contrast, EC/PC greater than EC/SC when TPR is above 10 mu/m2. The evaluation of the degree of pulmonary hypertension in infants with CTGV and IVSD should therefore be based not only on the absolute values of PC, EC, and TPR but also on such differential-diagnostic signs as the PC/SC, EC/SC, and EC/PC ratios.

Age Factors↗

PubMed1988

Clinical studies with captopril treatment of hypertensive patients.

Haemodynamic and humoral effects of captopril were studied in patients with essential and renovascular hypertension. Captopril decreased significantly both systolic and diastolic blood pressure and moderately, it reduced also the heart rate. On the basis of the haemodynamic effects our patients could be divided into two groups: in patients where the total peripheral resistance (TPR) exceeded 2000 dyn x sec x cm-5 during rest, captopril exerted its hypotensive effect by decreasing TPR. In patients in whom TPR was lower, the hypotensive action could be attributed to the reduction of cardiac output (CO). Captopril increased plasma renin activity, and decreased the activity of angiotensin converting enzyme (ACE) in the plasma. In acute study captopril did not influence plasma noradrenaline level but increased it during long-term administration. It did not affect dopamine or adrenaline levels. Captopril had no effect on plasma beta-endorphin concentration, moreover, the opiate antagonist, naloxone, failed to antagonize its antihypertensive effect. Comparing the acute effects of Capoten (Squibb, USA) and Tensiomin (EGIS, HUNGARY) no significant differences were found.

Biomechanical Phenomena↗

PubMed1985

Comparison of the haemodynamic profiles of the hypotensive action of verapamil and carvedilol.

Comparative haemodynamic investigations with carvedilol and verapamil were carried out on conscious, instrumented dogs. Arterial blood pressure, right atrial pressure (RAP), cardiac output (CO), heart rate, stroke volume and total peripheral resistance (TPR) were determined after intravenous (i.v.) injection of incremental doses (0.01-3 mg/kg) of the drugs. Carvedilol reduced the blood pressure in a dose-dependent manner, concomitant with a reduction in TPR. The RAP and the CO were not affected, indicating that arterial vasodilatation was induced by carvedilol. Verapamil showed a decrease in the blood pressure with a reduction of CO and SV. Moreover, at high doses the RAP was increased, indicating a reduction of the cardiac performance. Thus, in our experimental model remarkable differences between the haemodynamic effects of i.v. injections of carvedilol and verapamil have been observed, whereas after oral administration blood pressure also decreases after verapamil due to a reduction of TPR.

Animals↗

PubMed1985

Haemodynamic effects of the renin inhibitor SR 42128 in conscious baboons.

We studied the haemodynamic effects of captopril [3 mg/kg intravenously (i.v.)] and SR 42128 (8 mg/kg in a 30-min perfusion) in the conscious baboon after sodium depletion by furosemide. The evolution of the following parameters was studied: plasma renin activity (PRA), heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), first derivative of the left intraventricular pressure (dP/dt) and total peripheral resistance (TPR). Captopril (n = 5) increased PRA twofold and decreased MAP and TPR. Heart rate, CO and dP/dtmax were not significantly modified. As compared with a control group (n = 5), SR 42128 (n = 5) decreased PRA to almost undetectable levels for at least 2 h and decreased MAP, CO and TPR. It did not alter HR or dP/dtmax. Thus we can conclude that SR 42128 is a long-acting inhibitor of circulating renin in baboons and, in our experimental conditions, SR 42128, like captopril, induced a decrease in blood pressure without detrimental effect on cardiac function.

Animals↗

PubMed1986

Hemodynamic effects of nifedipine in hypertension in the presence of elevated angiotensin-II and beta-adrenergic blockade.

The hemodynamic effects of the slow release form of a calcium channel blocker, nifedipine retard, in essential hypertension patients after angiotensin II (AII) infusion were studied using nuclear ventriculography. Sublingual nifedipine lowered blood pressure that had been acutely raised by an infusion of AII to its baseline level. When used for 4 weeks, nifedipine retard maintained its blood-pressure-lowering effects without a change in heart rate, both when used alone and when used in addition to beta-adrenergic blockers. In the patients with untreated essential hypertension, nifedipine counteracted the lowering effect of AII on left ventricular ejection fraction (LVEF), which was 67.5 +/- 8.9% at recumbency, 61.2 +/- 6.6% (+/- SD) during AII infusion, and 72.1 +/- 7.5% 30 minutes after sublingual nifedipine. These acute effects seem to result from a marked reduction in total peripheral resistance (TPR) and are accompanied by a rise in cardiac index (CI). The TPR, in dynes/sec/cm-5, was 1376.9 +/- 275.8 at recumbency, 2000.7 +/- 358 during AII infusion, and 1228.6 +/- 289 30 minutes after sublingual nifedipine. The corresponding figures for CI in liters/M2 BSA, were 4.02 +/- 0.77, 3.03 +/- 0.64, and 4.32 +/- 0.79. In patients receiving beta-blocker therapy (propranolol or atenolol) with inadequate control of blood pressure, similar results were obtained in LVEF (69.7 +/- 8.87% at recumbency, 63.7 +/- 11.9% during AII infusion, and 72.2 +/- 6.05% 30 minutes after sublingual nifedipine). The initial TPR was much higher than that of untreated essential hypertensive patients. Nevertheless, the increase obtained during AII infusion was counteracted by sublingual nifedipine. CI was decreased by AII.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗

PubMed1986

Acute haemodynamic effects of the atrial natriuretic hormone in rats.

Haemodynamic effects of atriopeptin II (AP II) were determined in conscious and anaesthetized rats chronically instrumented with a Doppler flow probe on the ascending aorta. Intravenous injection of AP II (7 micrograms/kg) produced a decrease in mean arterial pressure within 5 min; however, a biphasic change occurred in total peripheral resistance (TPR). At 1 min in the anaesthetized rats, TPR decreased while cardiac output tended to increase, and similar changes occurred in the conscious rats. By 5-8 min the haemodynamic profile had reversed: cardiac output had decreased in both anaesthetized and conscious rats and TPR had increased in anaesthetized rats. Mean circulatory filling pressure (MCFP) was measured during brief circulatory arrest by inflating an intracardiac balloon. Blood volume was measured with 51Cr-erythrocytes and organ blood volume by whole-animal freezing in liquid nitrogen. There were no changes in MCFP in the conscious and the anaesthetized rats, nor in the blood volume or cardiopulmonary blood volume in the anaesthetized rats, at 5-7 min after AP II. Atriopeptin III (10 micrograms/kg intravenously) had no effects on MCFP and the blood volume in the conscious rats at 5 and 15 min after injection. These results suggest multiple mechanisms of action for the acute haemodynamic effects of atrial peptides.

Animals↗

PubMedDate not supplied

[Use of enalapril, an angiotensin-converting enzyme inhibitor, in pulmonary artery hypertension].

Enalapril (E) was used to treat 16 patients with pulmonary arterial hypertension, 6 primary and 10 secondary, 5 of the latter with congenital heart disease and 5 with chronic obstructive pulmonary disease. The average dose of E was 20 mg/day. All patients underwent pre and post-treatment cardiac catheterization with determination of pressures at: right atrial (RA), main pulmonary artery (MPA), pulmonary capillary wedge pressure ( VCP) and systemic arterial (SA). Resistances forces were also measured as; total pulmonary (TPR), pulmonary arteriolar (PAR) and total systemic (TSR) as well as cardiac output (CO), and echo and electrocardiograms, chest x ray, stress test and respiratory function test. The functional class (NYHA) improved in all (p less than 0.001). The initial mean pressures were: RA 12.24 +/- 4.35; MPA 73.81 +/- 25.16; VCP 12 +/- 2.73 and SA 89 +/- 14; TPR 1477 +/- 761; PAR 1243 +/- 730 and TSR 1684 +/- 505.5; CO 4.5 +/- 1.29. The final values were: RA 9.66 +/- 2.46 (p less than 0.001); MPA 63.26 +/- 24.45 (p less than 0.001); VCP 11.33 +/- 2.38 (p = NS); SA 81 +/- 10 (p less than 0.001); TPR 1009.5 +/- 536.7 (p less than 0.001); PAR 829 +/- 511.5 (p less than 0.001); TSR 1309.6 +/- 296.3 (p less than 0.001); CO 5.2 +/- 1.44 (p less than 0.001). The average of minutes on treadmill was initially 8.2 +/- 2.45 and final 12.46 +/- 3.0 (p less than 0.001). It is concluded that enalapril is a useful drug in the treatment of pulmonary arterial hypertension of any etiology.

Adult↗

PubMed1987

[Atrial natriuretic factor. Systemic and regional hemodynamic profile and interaction with the alpha-adrenergic system in pithed SHR rats].

The hemodynamic effects of ANF (1 and 5 micrograms/kg/min) and its potential interactions with the sympathetic system were investigated at the systemic and regional (pulsed Doppler) levels in the pithed SHR. ANF dose-dependently decreased cardiac output CO, renal (RBF), mesenteric (MBF) and hindquarter (HQBF) blood flows and increased the corresponding vascular resistances: total peripheral (TPR), renal (RR), mesenteric (MR) and hindquarter (HQR), all these effects being significant at 5 micrograms/kg/min. Mean blood pressure (MBP) and heart rate were also significantly decreased at 5 micrograms/kg/min. ANF significantly reduced the responses to cirazoline of MBP, TPR and RR (1 microgram/kg/min) and of MR (5 micrograms/kg/min) but did not affect those of HQR ANF also significantly reduced the responses to UK-14,304 of MBP, TPR and MR (5 micrograms/kg/min) but did not affect those of RR and HQR. These data indicate that (a) ANF, in the absence of reflex phenomenons, exerts intrinsic regional vasoconstrictor effects, (b) ANF exhibits a postsynaptic sympatho-inhibitory effect. The latter is more marked vs the alpha 1-(especially renal) than vs the alpha 2-adrenoceptor-mediated responses but does not affect the hindquarter vascular bed, which suggest that its contribution to the overall antihypertensive action of ANF is of limited importance.

Animals↗