Effects of central and peripheral angiotensin blockade in hypertensive rats

1978 ◽  
Vol 234 (5) ◽  
pp. H629-H637 ◽  
Author(s):  
J. F. Mann ◽  
M. I. Phillips ◽  
R. Dietz ◽  
H. Haebara ◽  
D. Ganten
Keyword(s):  
Blood Pressure ◽  
Renal Hypertension ◽  
Pressure Regulation ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Blood Pressure Decrease ◽  
Different Types ◽  
Angiotensin Blockade ◽  
The Brain ◽  
Goldblatt Hypertension

The angiotensin II (AII) antagonist [Sar1-Ala8]AII (Saralasin) was injected into the brain ventricles (IVT) and intravenously (IV) in five different types of hypertensive unanesthetized rats. Renal hypertension was studied 16-22 days after kidney clipping. Intravenous infusions of cumulative doses (0.1-100 microgram/kg per min) and IVT injections (5-40 microgram) of Saralasin did not change mean arterial pressure (MAP) in controls and in one-clip, one-kidney Goldblatt hypertension, whereas MAP decreased in one-clip, two-kidney Goldblatt hypertension following IV and IVT Saralasin. In two-clip, two kidney hypertensive rats, IVT Saralasin decreased MAP but was ineffective when infused IV. Both IV and IVT Saralasin increased MAP in DOC hypertension. In spontaneously hypertensive (SH) rats, IV Saralasin increased MAP; IVT injection decreased MAP. The effect of IVT Saralasin in SH rats persisted 15-20 h after nephrectomy. We conclude that plasma AII may contribute to peripheral and central mechanisms of blood pressure regulation. The dissociation of the effects of IV and IVT Saralasin and the persistance of blood pressure decrease in nephrectomized SH rats following IVT Saralasin further support a role for locally formed brain angiotensin.

scholarly journals Chronic immunoneutralization of brain angiotensin-(1-12) lowers blood pressure in transgenic (mRen2)27 hypertensive rats

2009 ◽  
Vol 297 (1) ◽  
pp. R111-R115 ◽  
Author(s):  
Katsunori Isa ◽  
Maria Antonia García-Espinosa ◽  
Amy C. Arnold ◽  
Nancy T. Pirro ◽  
Ellen N. Tommasi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Food Intake ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Rat Tissues ◽  
Pressure Regulation ◽  
Hypertensive Rats ◽  
Male Adult ◽  
The Brain

Angiotensin-(1-12) [ANG-(1-12)] is a newly identified peptide detected in a variety of rat tissues, including the brain. To determine whether brain ANG-(1-12) participates in blood pressure regulation, we treated male adult (mRen2)27 hypertensive rats (24–28 wk of age) with Anti-ANG-(1-12) IgG or Preimmune IgG via an intracerebroventricular cannula for 14 days. Immunoneutralization of brain ANG-(1-12) lowered systolic blood pressure (−43 ± 8 mmHg on day 3 and −26 ± 7 mmHg on day 10 from baseline, P < 0.05). Water intake was lower on intracereroventricular day 6 in the Anti-ANG-(1-12) IgG group, accompanied by higher plasma osmolality on day 13, but there were no differences in urine volume, food intake, or body weight during the 2-wk treatment. In Preimmune IgG-treated animals, there were no significant changes in these variables over the 2-wk period. The antihypertensive effects produced by endogenous neutralization of brain ANG-(1-12) suggest that ANG-(1-12) is functionally active in brain pathways regulating blood pressure.

Vasopressin in brain of spontaneously hypertensive rats

1982 ◽  
Vol 242 (4) ◽  
pp. H496-H499 ◽  
Author(s):  
W. Rascher ◽  
R. E. Lang ◽  
T. Unger ◽  
D. Ganten ◽  
F. Gross
Keyword(s):  
Blood Pressure ◽  
Plasma Concentration ◽  
Brain Stem ◽  
Spontaneously Hypertensive Rats ◽  
Age Groups ◽  
Plasma Osmolality ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto ◽  
The Brain

In stroke-prone spontaneously hypertensive rats (SHRSP) and in normotensive Wistar-Kyoto rats (WKY), arginine vasopressin (AVP) was measured by means of a radioimmunoassay in the plasma, the pituitary gland, the hypothalamus, and the brain stem. In 6- and 14-wk-old SHRSP, the plasma concentration of AVP was lower than in age-matched WKY (P less than 0.01), whereas it was elevated at 28 wk of age (P less than 0.01). In the pituitary of 6-wk-old SHRSP, AVP was higher than in WKY (P less than 0.05), but no such difference was found in older rats. In the hypothalamus and the brain stem, AVP content was reduced in all age groups of SHRSP. Plasma osmolality was diminished in 28-wk-old SHRSP only (P less than 0.01), whereas hematocrit in all age groups was higher in SHRSP than in WKY. It is concluded that the secretion of AVP and possibly its synthesis in the hypothalamus are reduced in SHRSP. Whether the reduced AVP content in the brain stem is related to the sustained elevation of blood pressure has to be studied further.

Microvascular Effects of Echinodorus grandiflorus on Cardiovascular Disorders

Planta Medica ◽  
2020 ◽  
Vol 86 (06) ◽  
pp. 395-404 ◽  
Author(s):  
Fabiana Gomes ◽  
André M. Marques ◽  
Obadia Nathalie ◽  
Marcos Adriano Lessa ◽  
Eduardo Tibiriçá ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Chronic Treatment ◽  
Spontaneously Hypertensive Rat ◽  
Microvascular Blood Flow ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Anti Inflammatory ◽  
The Brain

Abstract Echinodorus grandiflorus is a semiaquatic plant native to Brazil and belongs to the Alismataceae family. Infusion preparations of the leaves of this plant are often used due to its diuretic, blood pressure lowering, and anti-inflammatory properties. Our aim was to investigate the effects of chronic treatment with the crude hydroalcoholic extract of E. grandiflorus on central and peripheral microvascular changes induced in a model of hypertension and diabetes. The hemodynamic and microvascular effects of E. grandiflorus extract (50, 100, or 200 mg/kg/day for 28 days) or the isolated major diterpene from E. grandiflorus (3 to 10 mg/kg i. v.) were evaluated in spontaneously hypertensive rats using tail plethysmography and intravital fluorescence videomicroscopy, respectively, and were compared to vehicle-treated normotensive Wistar-Kyoto rats. We also investigated the protective effects of chronic treatment with E. grandiflorus (100 mg/kg/day) in brain capillary density and leukocyte-endothelium interactions on the brain vessels of DM-spontaneously (DM: diabetes mellitus) hypertensive rats. Chronically treating spontaneously hypertensive rats with increasing doses of crude hydroalcoholic E. grandiflorus extract resulted in significant dose-dependent reductions in systolic blood pressure and an anti-inflammatory effect on the brain microcirculation of DM-spontaneously hypertensive rat animals. Using laser speckle contrast imaging, we observed that intravenous administration of the major isolated clerodane diterpene metabolite (1 – 10 mg/kg) increased microvascular blood flow by 25% in spontaneously hypertensive rat skeletal muscle. The results of this study show that E. grandiflorus extracts can be useful in the prevention and reduction of microcirculatory damage in arterial hypertension and other diseases that involve microvascular dysfunction.

scholarly journals Effects of PPARγAgonist Pioglitazone on Redox-Sensitive Cellular Signaling in Young Spontaneously Hypertensive Rats

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ima Dovinová ◽  
Miroslav Barancik ◽  
Miroslava Majzunova ◽  
Stefan Zorad ◽  
Lucia Gajdosechová ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Intracellular Signaling ◽  
Experimental Hypertension ◽  
Pressure Regulation ◽  
Insulin Stimulation ◽  
Hypertensive Rats ◽  
Sod Activity ◽  
Spontaneously Hypertensive ◽  
Vascular Contractility ◽  
Signaling Components

PPARγreceptor plays an important role in oxidative stress response. Its agonists can influence vascular contractility in experimental hypertension. Our study was focused on the effects of a PPARγagonist pioglitazone (PIO) on blood pressure regulation, vasoactivity of vessels, and redox-sensitive signaling at the central (brainstem, BS) and peripheral (left ventricle, LV) levels in young prehypertensive rats. 5-week-old SHR were treated either with PIO (10 mg/kg/day, 2 weeks) or with saline using gastric gavage. Administration of PIO significantly slowed down blood pressure increase and improved lipid profile and aortic relaxation after insulin stimulation. A significant increase in PPARγexpression was found only in BS, not in LV. PIO treatment did not influence NOS changes, but had tissue-dependent effect on SOD regulation and increased SOD activity, observed in LV. The treatment with PIO differentially affected also the levels of other intracellular signaling components: Akt kinase increased in the the BS, whileβ-catenin level was down-regulated in the BS and up-regulated in the LV. We found that the lowering of blood pressure in young SHR can be connected with insulin sensitivity of vessels and thatβ-catenin and SOD levels are important agents mediating PIO effects in the BS and LV.

scholarly journals Effects of Different Types of Yam (Dioscorea alata) Products on the Blood Pressure of Spontaneously Hypertensive Rats

2009 ◽  
Vol 73 (6) ◽  
pp. 1371-1376 ◽  
Author(s):  
Yuh-Hwa LIU ◽  
Yin-Shiou LIN ◽  
Der-Zen LIU ◽  
Chuan-Hsiao HAN ◽  
Ching-Tan CHEN ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Dioscorea Alata ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Different Types
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