Short-term effect of egg-white hydrolysate products on the arterial blood pressure of hypertensive rats

2005 ◽  
Vol 94 (5) ◽  
pp. 731-737 ◽  
Author(s):  
Marta Miguel ◽  
Rosina López-Fandiño ◽  
Mercedes Ramos ◽  
Amaya Aleixandre
Keyword(s):  
Blood Pressure ◽  
Egg White ◽  
Therapeutic Benefit ◽  
Negative Control ◽  
Hypertensive Rats ◽  
Blood Pressure Lowering Effect ◽  
Wky Rats ◽  
Arterial Blood ◽  
Wistar Kyoto

In the present study we evaluate the blood pressure-lowering effect of the following products: the hydrolysate obtained from egg white (EW) by enzymatic treatment with pepsin (HEW), the peptide fraction of HEW with molecular mass lower than 3000 Da (HEW<3000 Da), and three peptide sequences isolated from HEW<3000 Da (Tyr-Ala-Glu-Glu-Arg-Tyr-Pro-Ile-Leu: YAEERYPIL); (Arg-Ala-Asp-His-Pro-Phe-Leu: RADHPFL); and (Ile-Val-Phe (IVF)). These peptides, and also HEW and HEW<3000 Da, had been characterized previously in vitro as potent inhibitors of angiotensin-converting enzyme (ACE). EW and the products mentioned earlier were orally administered by gastric intubation, to 17–20-week-old male spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto (WKY) rats. We measured the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) of the rats by the tail cuff method before administration and also 2, 4, 6, 8 and 24h post-administration. Distilled water served as negative control, and we used captopril (50mg/kg) as positive control to carry out similar experiments with a known ACE inhibitor. HEW, HEW<3000 Da and the three peptide sequences decreased SBP and DBP in SHR but they did not modify these variables in WKY rats. The peptide sequences YAEERYPIL, RADHPFL and IVF showed a potency to decrease blood pressure greater than HEW or HEW<3000 Da. The results obtained suggest that the studied products could be used as a functional food with potential therapeutic benefit in the prevention and treatment of hypertension.

Maternal influences on sympathetic-adrenal medullary system in spontaneously hypertensive rats

1990 ◽  
Vol 258 (5) ◽  
pp. H1312-H1316
Author(s):  
M. A. Cierpial ◽  
M. Konarska ◽  
R. McCarty
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Acute Stress ◽  
Hypertensive Rats ◽  
Blood Pressure Lowering Effect ◽  
Maternal Environment ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Wistar Kyoto ◽  
Cross Fostering

The technique of reciprocal cross fostering was used to assess the influence of the maternal environment on the functioning of the sympathetic-adrenal medullary system in the spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) normotensive rats. Control, in-fostered, and cross-fostered rats were tested in adulthood to assess 1) the neural contribution to resting mean arterial blood pressure (MAP) and 2) sympathetic-adrenal medullary responses to acute footshock stress. Adult resting MAP was significantly lower in cross-fostered SHRs (139.6 mmHg) compared with control or in-fostered SHRs (162.1 and 159.3 mmHg). In addition, the decrease in MAP after sympathetic blockade (40.6 mmHg) was significantly less in cross-fostered SHRs compared with controls (50.1 mmHg). Sympathetic-adrenal medullary responses to foot-shock were greater in SHR than WKY rats; however, cross-fostered SHRs showed exaggerated responses compared with control and in-fostered SHRs. Altering the maternal environment did not produce any measurable effects on the neural contribution to resting MAP or sympathetic-adrenal medullary responsivity to acute stress in the WKY strain. These results indicate that the blood pressure-lowering effect of cross fostering in the SHR strain is caused in part by a dampening of the neural contribution to resting MAP; however, these animals retain their strain's characteristic adrenergic hyperreactivity to stressful stimulation.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

5-HT2B-receptor antagonist LY-272015 is antihypertensive in DOCA-salt-hypertensive rats

1999 ◽  
Vol 276 (3) ◽  
pp. H944-H952 ◽  
Author(s):  
Stephanie W. Watts ◽  
Gregory D. Fink
Keyword(s):  
Blood Pressure ◽  
Receptor Antagonist ◽  
High Blood Pressure ◽  
Reduce Blood Pressure ◽  
Receptor Expression ◽  
Hypertensive Rats ◽  
Arterial Blood ◽  
Salt Hypertension

We previously demonstrated a change in the receptors mediating 5-hydroxytryptamine (5-HT)-induced contraction in arteries of deoxycorticosterone acetate (DOCA)-salt-hypertensive rats. Specifically, contraction to 5-HT is mediated primarily by 5-HT2A receptors in arteries from normotensive sham rats and by both 5-HT2A and 5-HT2B receptors in arteries from hypertensive rats. We hypothesized that the 5-HT2B receptor may play a role in maintaining the high blood pressure of DOCA-salt-hypertensive rats, and herein we provide data connecting in vitro and in vivo findings. The endothelium-denuded isolated superior mesenteric artery of DOCA-salt rats displayed a marked increase in maximum contraction to the newly available 5-HT2B-receptor agonist BW-723C86 compared with that of arteries from sham rats, confirming that the 5-HT2B receptor plays a greater role in 5-HT-induced contraction in arteries from DOCA-salt rats. In chronically instrumented rats, the 5-HT2B-receptor antagonist LY-272015 (0.3, 1.0, and 3.0 mg/kg iv at 30-min intervals) was given cumulatively 1 time/wk during 4 wk of continued DOCA-salt treatment. LY-272015 did not reduce blood pressure of the sham-treated rats at any time or dose. However, LY-272015 (1.0 and 3.0 mg/kg) significantly reduced mean blood pressure in a subgroup of week 3 (−20 mmHg) and week 4 DOCA-salt (−40 mmHg) rats that had extremely high blood pressure (mean arterial blood pressure ∼200 mmHg). Blockade of 5-HT2Breceptors by in vivo administration of LY-272015 (3.0 mg/kg) was verified by observing reduced 5-HT-induced contraction in rat stomach fundus, the tissue from which the 5-HT2B receptor was originally cloned. These data support the novel hypothesis that 5-HT2B-receptor expression is induced during the development of DOCA-salt hypertension and contributes to the maintenance of severe blood pressure elevations.

scholarly journals Effect of a methionine-supplemented diet on the blood pressure of Wistar–Kyoto and spontaneously hypertensive rats

2003 ◽  
Vol 89 (4) ◽  
pp. 539-548 ◽  
Author(s):  
Sophie Robin ◽  
Véronique Maupoil ◽  
Frédérique Groubatch ◽  
Pascal Laurant ◽  
Alain Jacqueson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Homocysteine ◽  
Shr Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Complex Interactions ◽  
Methionine Concentration ◽  
Wistar Kyoto

The objectives of the present work were to evaluate the effect of a methionine-supplemented diet as a model of hyperhomocysteinaemia on the systolic blood pressure (BP) and vasomotor functions of aortic rings in Wistar–Kyoto (WKY) and spontaneously hypertensive rats (SHR). WKY and SHR rats, randomised into four groups, were fed a normal semisynthetic diet or a methionine (8 g/kg)-supplemented diet for 10 weeks. Systolic BP was measured non-invasively. At the end of the experiment, plasma homocysteine, methionine, cysteine and glutathione levels were determined. Vasoconstriction and vasodilatation of aortic rings were measured. The methionine-supplemented diet induced a significant increase in plasma homocysteine and methionine concentration in both WKY and SHR rats, an increase in plasma cysteine concentrations in WKY rats and an increase in the glutathione concentration in SHR. The systolic BP of WKY rats fed the methionine-supplemented diet increased significantly (P<0·01), whereas systolic BP was reduced in SHR. An enhanced aortic responsiveness to noradrenaline and a decreased relaxation induced by acetylcholine and bradykinin were observed in the WKY rats fed the methionine-enriched diet. In SHR, the bradykinin-induced relaxation was reduced, but the sodium nitroprusside response was increased. In conclusion, a methionine-enriched diet induced a moderate hyperhomocysteinaemia and an elevated systolic BP in WKY rats that was consistent with the observed endothelial dysfunction. In SHR, discrepancies between the decreased systolic BP and the vascular alterations suggest more complex interactions of the methionine-enriched diet on the systolic BP. Further investigations are needed to understand the paradoxical effect of a methionine-rich diet on systolic BP.

Myocardial meta-[125I]iodobenzylguanidine uptake in awake genetically hypertensive rats at different ages: an autoradiographic study

1999 ◽  
Vol 77 (6) ◽  
pp. 398-406 ◽  
Author(s):  
Carole Schwebel ◽  
Andrée Durand ◽  
Diane Godin-Ribuot ◽  
Olivier Provendier ◽  
Pierre Demenge
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Weight Ratio ◽  
Autoradiographic Study ◽  
Mibg Uptake ◽  
Hypertensive Rats ◽  
Heterogeneous Distribution ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Arterial Blood ◽  
Wistar Kyoto

The purpose of this work was to evaluate changes in myocardial meta-[125I]iodobenzylguanidine ([125I]MIBG) uptake and distribution with age in awake spontaneously hypertensive rats (SHR) with respect to Wistar-Kyoto (WKY) rats. Rats were randomly divided into two groups, one for measuring myocardial [125I]MIBG uptake and distribution 4 h after its injection and the second for evaluating myocardial catecholamine concentrations. Mean arterial blood pressure, cardiac hypertrophy index (heart/body weight ratio), and heart rate were significantly higher with increasing age in SHR compared with matched WKY rats. Myocardial catecholamine concentrations and turnover did not differ between the two strains and were significantly decreased with increasing age. Myocardial [125I]MIBG uptake determined by gamma counting was similar in WKY rats and SHR and did not vary significantly with age when expressed as uptake density. However, in both strains of rats, [125I]MIBG uptake determined by autoradiography was significantly greater at the base of the heart than at the apex and midventricular levels, and the uptake values of young rats were significantly higher than those of older rats. In 21-week-old WKY rats and SHR, the highest [125I]MIBG uptake values were found in the right ventricle. Thus, quantitative autoradiography allowed detection of significant changes in myocardial [125I]MIBG uptake and showed its heterogeneous distribution in the rat heart.Key words: spontaneously hypertensive rats (SHR), Wistar-Kyoto rats, myocardial meta-[125I]iodobenzylguanidine uptake, sympathetic drive.

Glomerular prostaglandin formation in two-kidney, one-clip hypertensive rats

1984 ◽  
Vol 247 (6) ◽  
pp. F975-F981 ◽  
Author(s):  
R. A. Stahl ◽  
U. Helmchen ◽  
M. Paravicini ◽  
L. J. Ritter ◽  
P. Schollmeyer
Keyword(s):  
Blood Pressure ◽  
Filtration Rate ◽  
In Vivo Studies ◽  
Cyclooxygenase Inhibitor ◽  
Severe Damage ◽  
Hypertensive Rats ◽  
Cyclooxygenase Inhibition ◽  
Arterial Blood

In vitro prostaglandin (PG) and thromboxane B2 (TXB2) formation by isolated glomeruli from normotensive (N) and two-kidney, one-clip hypertensive (2K,1C) rats was determined. When calculated on the basis of glomerular protein content, PGE2, 6-keto-PGF1 alpha and TXB2 production of glomeruli from clipped kidneys was significantly greater than PG and TXB2 formation of glomeruli from the untouched kidneys. When PG and TXB2 formation was calculated per amount of glomeruli, only PGE2 formation was found to be significantly greater in clipped kidneys. No severe damage of glomerular structure was found in the kidneys when studied by light microscopy. In additional in vivo studies, the effect of the cyclooxygenase inhibitor indomethacin on blood pressure and glomerular filtration rate (GFR) was evaluated. Following indomethacin GFR in 7 of 13 clipped kidneys of 2K,1C rats decreased from 363 +/- 77 to 188 +/- 51 microliter/100 g body wt, whereas six kidneys developed anuria. No effect of cyclooxygenase inhibition on GFR was found in N rats and in untouched kidneys of 2K,1C rats. Mean arterial blood pressure in 2K,1C hypertension fell significantly, from 158 +/- 10 to 135 +/- 7 mmHg, after cyclooxygenase inhibition. No effect was seen in N rats. The data suggest that increased glomerular PG formation in the clipped kidneys of 2K,1C rats is involved in the pathogenesis of hypertension in this animal model.

Effects of Bromocriptine on Blood Pressure and Plasma β-Endorphin in Spontaneously Hypertensive Rats

1981 ◽  
Vol 61 (s7) ◽  
pp. 343s-345s ◽  
Author(s):  
J. S. Hutchinson ◽  
R. Di Nicolantonio ◽  
A. Lim ◽  
J. Clements ◽  
J. W. Funder
Keyword(s):  
Blood Pressure ◽  
Plasma Levels ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Intravenous Injections ◽  
Wky Rats ◽  
Wistar Kyoto

1. Immunoreactive β-endorphin (IR-βEP) was two- to three-fold higher in pituitary neuro-intermediate lobes (N-IL) of spontaneously hypertensive rats (SHR) than of normotensive Wistar—Kyoto (NT-WKY) controls. 2. Plasma levels of IR-βEP were lower in SHR than in NT-WKY rats. 3. Intravenous injections of morphine lowered blood pressure of both SHR and NT-WKY rats to the same level; naloxone restored blood pressure of both groups to pre-morphine values. 4. Infusion of bromocriptine in SHR for 1 week lowered blood pressure and N-IL IR-βEP concentration. 5. These results confirm and extend postulated dopaminergic defect in this model of hypertension.

scholarly journals Changes in arterial blood pressure in hypertensive rats caused by long-term intake of milk fermented by Enterococcus faecalis CECT 5728

2005 ◽  
Vol 94 (1) ◽  
pp. 36-43 ◽  
Author(s):  
M. Miguel ◽  
B. Muguerza ◽  
E. Sánchez ◽  
M. A. Delgado ◽  
I. Recio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Inhibitory Activity ◽  
Tap Water ◽  
Fermented Milk ◽  
Negative Control ◽  
Hypertensive Rats ◽  
Ace Inhibitory Activity ◽  
Arterial Blood ◽  
Ace Inhibitory

We have evaluated the changes in arterial blood pressure caused in spontaneously hypertensive rats (SHR) by long-term intake of an Enterococcus faecalis CECT 5728-fermented milk with significant angiotensin-converting enzyme (ACE)-inhibitory activity. After being weaned, male 3-week-old SHR were randomized into five groups. Until the 20th week of life, rats in each group were given one of the following drinking fluids: tap water (negative control 1), a fermented milk without ACE-inhibitory activity (negative control 2), captopril (100 mg/kg) (positive control), the E. faecalis CECT 5728-fermented milk that had significant ACE-inhibitory activity, or Ca-enriched E. faecalis CECT 5728-fermented milk. Animals in the different groups were then given tap water as drinking fluid from the 20th to 25th week of life. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly in the rats, from the 6th to 25th week of life, by the tail-cuff method. A definite decrease in SBP and DBP could be observed in the rats treated with captopril and also in the rats that received the E. faecalis CECT 5728-fermented milks. The greatest antihypertensive effect was observed when the pharmacological treatment was administered. The effect of the Ca-enriched fermented milk was slightly more accentuated and more constant than the effect of the E. faecalis CECT 5728-fermented milk that had not been enriched in Ca. SBP and DBP increased in the treated SHR when the corresponding antihypertensive treatment was removed. Fermentation of milk with E. faecalis CECT 5728 may therefore be a successful strategy to produce a functional food with antihypertensive activity.

scholarly journals Exaggerated postnatal surge of orexin and the effects of elimination of excess orexin on blood pressure in spontaneously hypertensive rats in postnatal development

2020 ◽  
Author(s):  
Savannah Barnett ◽  
Ruhong Dong ◽  
Logan Briggs ◽  
Alexander Moushey ◽  
Aihua Li
Keyword(s):  
Blood Pressure ◽  
Postnatal Development ◽  
Arterial Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Neurogenic Hypertension ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
New Findings ◽  
Wistar Kyoto

AbstractIt has been established that an overactive orexin (OX) system is associated with neurogenic hypertension in spontaneously hypertensive rats (SHRs). However, the chronology and mechanism of such association between orexin system and hypertension is unclear. We hypothesized that an aberrant surge of OX neurons in SHRs precedes the aberrant increase of arterial blood pressure (ABP) during postnatal development, which was primarily contributed by the exaggerated postnatal OX neurogenesis. We found that (1) SHRs experienced a greater surge in the number of orexin neurons than normotensive Wistar-Kyoto (WKY) rats before P16, which led to significantly more OX neurons than age-matched controls by P15-16 (3680±219 vs 2407±182, respectively, P=0.002). (2) Exaggerated OX neurogenesis, marked by bromodeoxyuridine (BrdU), was the primary contributor to excessive OX neurons in SHRs during development. (3) In contrast, SHRs and normotensive control rats have similar mean arterial blood pressure (ABP) at P15, and a significantly higher ABP in SHR than WKY emerges at P20 (74.8 ± 2.5 vs 66.9 ± 4.4 mmHg in wakefulness, respectively, P<0.05), a few days following the surge of OX activity. (4) Selectively eliminating excess (∼30%) orexin neurons, via a targeted neurotoxin, in SHRs between P30 and P40 results in a significantly lowered ABP compared to non-lesioned SHRs at P40. We suggest that the postnatal surge of OX neurons, primarily attributed to the exaggerated postnatal OX neurogenesis, may be necessary for the development of higher ABP in SHRs, and modulation of the overactive OX system may have a preventative effect during the pre-hypertensive period.New FindingsWhat is the central question of this study?Excess orexin neurons have been associated with hypertension in spontaneously hypertensive rats, however, the association and mechanism between developing excess orexin neurons and high blood pressure are unknown.What is the main finding and its importance?Using spontaneously hypertensive rats in anatomical and physiological studies, we provided evidence showing that the excess OX neurons, primarily via exaggerated OX neurogenesis, may be necessary in developing a higher ABP in SHRs during development, and modulation of the overactive orexin system may be beneficial in treating hypertension.

Baroreflex Sensitivity during the Development of Spontaneous Hypertension in Rats

1982 ◽  
Vol 62 (6) ◽  
pp. 589-594 ◽  
Author(s):  
H. A. J. Struyker-Boudier ◽  
R. T. Evenwel ◽  
J. F. M. Smits ◽  
H. Van Essen
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Baroreceptor Reflex ◽  
Spontaneous Hypertension ◽  
Wky Rats ◽  
Arterial Blood ◽  
A Value ◽  
Freely Moving ◽  
Wistar Kyoto ◽  
Further Development

1. Baroreflex sensitivity was studied in relation to the development of spontaneous hypertension in rats (SH rats), with normotensive Wistar-Kyoto (WKY) rats as controls. Conscious, freely moving animals were studied at different times, ranging from 4 to 20 weeks after birth. 2. The youngest SH rats (4–6 weeks; n = 10) already had significantly (P < 0.01) higher mean arterial blood pressure (112 ± 2 mmHg) than WKY rats of corresponding age (95 ± 4 mmHg; n = 10). Baroreflex sensitivity did not differ at this age (0.37 ± 0.04 vs 0.38 ± 0.05 ms/mmHg). 3. Mean arterial pressure increased rapidly in SH rats during further development, reaching a value of 166 ± 3 mmHg in 12–20 week old animals (n = 25). In equally old WKY rats blood pressure was significantly (P<0.001) lower (110 ± 6 mmHg, n = 25). Baroreflex sensitivity did not change during development of SH rats (0.40 ± 0.03 ms/mmHg in 12–20 weeks old SH rats), whereas it increased two- to three-fold in WKY rats (0.93 ± 0.08 ms/mmHg, P<0.001). 4. It is concluded that an increase in baroreflex sensitivity is part of the development of a normotensive cardiovascular system, whereas in SH rats responsiveness of the baroreceptor reflex remains depressed during the development and stabilization of hypertension.

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