scholarly journals Polyphenolic Composition and Hypotensive Effects of Parastrephia quadrangularis (Meyen) Cabrera in Rat

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 591 ◽  
Author(s):  
Fredi Cifuentes ◽  
Javier Palacios ◽  
Chukwuemeka Nwokocha ◽  
Jorge Bórquez ◽  
Mario Simirgiotis ◽  
...  
Keyword(s):  
Cardiac Contractility ◽  
Folk Medicine ◽  
Negative Inotropic Effect ◽  
Cytosolic Calcium ◽  
Rat Aorta ◽  
Sprague Dawley ◽  
The Andes ◽  
Polyphenolic Composition ◽  
Sprague Dawley Rats ◽  
Blood Pressures

Parastrephia quadrangularis (Pq), commonly called “Tola”, is widely used in folk medicine in the Andes, including for altitude sickness. In this study, polyphenolic composition was determined, and hypotensive effects were measured; the ethnopharmacological use as hypotensive was related to the presence of phenolic compounds. For this purpose, male Sprague-Dawley rats (6 to 8 weeks of age, 160 to 190 g) were fed Pq extract (10 to 40 mg/kg) for 10 days through gavage. Blood pressures and heart rate were significantly (p < 0.01) reduced in normotensive rats receiving Pq extract (40 mg/kg body weight). Pq extract induced a negative inotropic effect, and endothelium-dependent vasodilation mediated by nitric oxide (NO). Furthermore, preincubation with Pq extract significantly decreased the cytosolic calcium on vascular smooth muscle cells A7r5 in response to L-phenylephrine (PE). Seven metabolites were isolated from the Pq extract, but three flavonoids (10−4 M) showed similar vasodilation to the extract in intact rat aorta as follows: 5,3′,4′-trihydroxy-7-methoxyflavanone (2); 3,5,4′-trihydroxy-7,8,3′-trimethoxyflavone (6); and 5,4′-dihydroxy-3,7,8,3′-tetramethoxyflavone (7). The Pq extract and compounds 2 and 7 significantly (p < 0.05) reduced the contraction to Bay K8644 (10 nM, an agonist of CaV1.2 channels). Administration of Pq decreased cardiac contractility and increased endothelium-dependent and -independent vasodilation.

Abstract 16993: Sex Differences in Renal Transporter Profile Indicate Lower Proximal Reabsorption in Females

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Luciana C Veiras ◽  
An Tran ◽  
Donna L Ralph ◽  
Adriana Castello Costa Girardi ◽  
Alicia A McDonough
Keyword(s):  
Distal Tubule ◽  
Sprague Dawley ◽  
Volume Load ◽  
Sprague Dawley Rats ◽  
Lower Blood ◽  
Functional Consequences ◽  
Blood Pressures ◽  
Renal Transporter ◽  
Pressure Natriuresis ◽  
Quantitative Immunoblotting

Females have lower blood pressure than males before menopause, blunted hypertensive response to AngII, and a leftward shift in pressure natriuresis. Estrogen decreases renal ACE and AT1R and increases NO and AT2R. At the renal transporter level, distal tubule Na+-Cl- cotransporter (NCC) is upregulated by estrogen and more abundant in females, while the loop of Henle (LH) Na+-K+-2Cl- cotransporter (NKCC2) is less abundant. This study aimed to compare female to male apical Na+ transporters’ abundance, distribution, phosphorylation and cleavage and to determine the functional consequences of the differences. Sprague Dawley rats were fasted overnight then fed a 0%KCl meal before termination. The figure displays relative abundance of total and modified (P -phosphorylated, CL-cleaved, FL-full length) transporters expressed along the nephron in females versus males (defined as 1.0), determined by quantitative immunoblotting. Lower abundance of NaPi2, villin, myosin VI, together with higher NHE3-P (inactivation marker) suggest less proximal tubule (PT) reabsorption in females. Confocal immunohistochemistry confirmed that NHE3 localized to the base of the PT microvilli in females (not males) and endogenous CLi+, a marker of volume leaving the PT, was twice as high in females than males. While LH NKCC2 and its regulatory kinase SPAK were not significantly different, distal NCC, and activated NCC-P were more abundant in females, although thiazide sensitive natriuresis was not greater. ENaC α and γ subunits were more activated (-CL) in females. A saline challenge (7% of b.w. saline, i.p.) demonstrated that females excreted a saline load more rapidly than males. Taken together, these results suggest that lower proximal transporters and reabsorption provoke a volume load dependent elevation in NCC and ENaC. This profile in females likely facilitates pressure natriuresis and maintains lower blood pressures.

Abstract P214: The Non-canonical Stress Tolerance Cascade for Toll-like Receptor 9 in the Vasculature Signals Through Liver Kinase B1

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Cameron G McCarthy ◽  
Camilla F Wenceslau ◽  
Safia Ogbi ◽  
Theodora Szasz ◽  
R.Clinton Webb
Keyword(s):  
Protein Kinase ◽  
Stress Tolerance ◽  
Vascular Function ◽  
Cytosolic Calcium ◽  
Toll Like Receptor ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Liver Kinase B1 ◽  
Tlr9 Activation

Toll-like receptor (TLR)9 is a pattern recognition receptor of the innate immune system. Recently, a non-canonical stress tolerance pathway has been reported for TLR9 in non-immune cells (cardiomyocytes and neurons), independent of inflammatory signaling. It was observed that TLR9 inhibited sarco/endoplasmic reticulum Ca 2+ -ATPase (SERCA)2, increasing cytosolic calcium, and resulting in 5’ AMP-activated protein kinase (AMPK)α activation. In our laboratory, we have reported that TLR9 treatment in vivo causes arterial dysfunction that contributes to the pathogenesis of hypertension and that these phenotypes occurred in conjunction with vascular AMPKα phosphorylation (Thr172). However, whether a dysregulation in calcium homeostasis via the non-canonical stress tolerance cascade underlies the impaired vascular function after TLR9 stimulation needs to be clarified. We hypothesized that TLR9 activation would inhibit SERCA2 activity in the vasculature. SERCA2 activity was assessed using a luciferase-based ATP quantification kit. Microsomes were isolated from pooled aortae of Sprague-Dawley rats and subjected to treatment with either Vehicle (Veh) or ODN2395 (2 μM), with or without a SERCA2 inhibitor (thapsigargin; 1 μM). The presence of thapsigargin increased ATP concentrations similarly in both Veh and ODN2395 [ATP (μM), Veh: 19±3 vs. Veh+thapsigargin: 140±35; ODN2395: 22±9 vs. ODN2395+thapsigargin: 129±12, both p<0.05], suggesting TLR9 activation did not inhibit SERCA2 activity. Next, MRA from Sprague-Dawley rats were divided into three sections for Western blot analysis of AMPKα-activating kinases, specifically calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and liver kinase B1 (LKB1). ODN2395 alone did not increase protein expression of phospho-CaMKK2 Ser511 (p>0.05), again suggesting calcium-independent activation of AMPKα. However, ODN2395 did increase phospho-LKB1 Ser428 (3.8 fold vs. Veh, p<0.05), and this increase in expression was inhibited by pre-incubation with TLR9 antagonist ODN2088 (20 μM) (p>0.05). These results suggest that the TLR9 non-canonical stress tolerance pathway in the vasculature is mediated by LKB1, and not SERCA2 inhibition.

Sexual dimorphism in vasopressin-induced contraction of rat aorta

1991 ◽  
Vol 260 (2) ◽  
pp. H453-H458 ◽  
Author(s):  
J. N. Stallone ◽  
J. T. Crofton ◽  
L. Share
Keyword(s):  
Estrous Cycle ◽  
Vascular Reactivity ◽  
Rat Aorta ◽  
Isometric Tension ◽  
Female Rats ◽  
Male Rats ◽  
Maximal Response ◽  
Sprague Dawley ◽  
Tension Development ◽  
Sprague Dawley Rats

Previously, we reported that, in the rat, pressor responsiveness to vasopressin (VP) is higher in males than in females during most phases of the estrous cycle. To explore the role of the vasculature in this phenomenon, we examined vascular reactivity to VP in thoracic aortas of male rats and female rats during each phase of the estrous cycle. Aortic rings were prepared from age-matched male and female Sprague-Dawley rats and mounted for isometric tension recording. Maximal response of female aortas to VP (4,246 +/- 163 mg/mg ring dry wt) was more than twice (P less than 0.001) that of male aortas (1,877 +/- 215 mg/mg ring wt). Sensitivity of female aortas to VP was substantially higher (P less than 0.001) than that of male aortas (EC50: 10.9 +/- 0.7 vs. 19.0 +/- 1.6 nM, respectively). Maximal rate of tension development (dT/dtmax) during contraction with VP was nearly twofold higher (P less than 0.01) in female aortas (536 +/- 23 mg/min) than in male aortas (300 +/- 19 mg/min). Maximal response, sensitivity, and dT/dtmax of female aortas did not vary significantly during the estrous cycle. Maximal response of female aortas to phenylephrine (PE; 1,251 +/- 93 mg/mg ring wt) was half that (P less than 0.001) of male aortas (2,546 +/- 194 mg/mg ring wt); sensitivity to PE did not differ significantly (EC50: 0.33 +/- 0.02 vs. 0.38 +/- 0.06 microM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Portal hypertension increases vasoconstrictor responsiveness of rat aorta

1999 ◽  
Vol 96 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Claire CONNOLLY ◽  
Teresa CAWLEY ◽  
P. Aiden MCCORMICK ◽  
James R. DOCHERTY
Keyword(s):  
Portal Hypertension ◽  
Wistar Rats ◽  
Rat Aorta ◽  
Maximum Response ◽  
Sprague Dawley ◽  
Portal Vein Stenosis ◽  
Sprague Dawley Rats ◽  
Significant Difference ◽  
Hepatic Portal

We have examined the effects of pre-hepatic portal hypertension on the responsiveness of aorta from Wistar and Sprague–Dawley rats. Rats were made portal hypertensive by creating a calibrated portal vein stenosis, or sham operated. In rat aorta, there was no significant difference between portal hypertensive and sham-operated animals in the contractile potency of KCl, noradrenaline or phenylephrine. In aortas from Wistar rats, the maximum response to KCl (0.71±0.12 ;g) and noradrenaline (1.00±0.17 ;g) but not phenylephrine (0.86±0.10 ;g) in portal hypertensive animals was significantly increased compared with that in sham-operated animals (0.45±0.04 ;g, 0.57±0.07 ;g, 0.71±0.05 ;g respectively). In aortas from Sprague–Dawley rats, the maximum response to KCl (1.21±0.21 ;g) and phenylephrine (1.54±0.30 ;g) but not noradrenaline (0.93±0.09 ;g) in portal hypertensive animals was significantly increased compared with that in sham-operated animals (0.59±0.09 ;g, 0.76±0.11 ;g, 1.04±0.10 ;g respectively). There was no difference between portal hypertensive and sham-operated Wistar rats in the affinity or maximum number of binding sites for [3H]prazosin to α1-adrenoceptors in cardiac ventricular membranes. It is concluded that portal hypertension tends to produce an increase rather than a decrease in the contractile response to vasoconstrictors in aorta from both Wistar and Sprague–Dawley rats. This suggests that the diminished responsiveness to vasoconstrictors reported in portal hypertensive rats in vivo is not due to a diminished responsiveness at the level of the vascular smooth muscle.

Antihypertensive effect of progesterone in rats with mineralocorticoid-induced hypertension.

1979 ◽  
Vol 236 (4) ◽  
pp. E366 ◽  
Author(s):  
G Wambach ◽  
J R Higgins
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Hypotensive Effect ◽  
Sodium Concentration ◽  
Sprague Dawley ◽  
Spontaneously Hypertensive ◽  
Sprague Dawley Rats ◽  
Induced Hypertension ◽  
Blood Pressures ◽  
Induced Changes

Uninephrectomized, saline-fed male Sprague-Dawley rats were given DOCA 5 mg per week alone or together with progesterone 20 mg per week for 6 weeks (phase I). Subsequently, the doses of DOCA and progesterone were doubled and the rats were studied for an additional 6 wk (phase II). Progesterone prevented DOCA-induced hypertension during phase I. Phase II blood pressures were higher in DOCA-progesterone-treated animals than in controls, but remained lower than in animals treated with DOCA alone. At the end of phase II the animals were killed, and blood samples and skeletal muscle samples were taken for analysis of electrolyte content. DOCA-treated animals were found to have an increased rate of potassium excretion, an increase in muscle sodium concentration, and a decrease in muscle potassium concentration compared to the controls. Progesterone treatment significantly blunted the DOCA-induced changes in muscle electrolyte concentrations and increased the rate of sodium excretion. No hypotensive effect was observed when progesterone in doses similar to those of phase I was administered to spontaneously hypertensive rats. Thus, in experimental mineralocorticoid hypertension, the hypotensive effect of progesterone appears to correlate closely with its mineralocorticoid antagonistic properties.

Contractile response of normotensive rat aorta to serum from salt-loaded Sprague-Dawley rats

1993 ◽  
Vol 423-423 (1-2) ◽  
pp. 161-163 ◽  
Author(s):  
O. A. Sofola ◽  
P. C. M. Obiefuna ◽  
B. J. Adegunloye
Keyword(s):  
Contractile Response ◽  
Rat Aorta ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

Connexin mimetic peptides fail to inhibit vascular conducted calcium responses in renal arterioles

2008 ◽  
Vol 295 (3) ◽  
pp. R840-R847 ◽  
Author(s):  
Charlotte Mehlin Sorensen ◽  
Max Salomonsson ◽  
Thomas Hartig Braunstein ◽  
Morten Schak Nielsen ◽  
Niels-Henrik Holstein-Rathlou
Keyword(s):  
Electrical Current ◽  
Vascular Wall ◽  
Rat Aorta ◽  
Sprague Dawley ◽  
Renal Vasculature ◽  
Microcirculatory Blood Flow ◽  
Sprague Dawley Rats ◽  
Resistance Vessels ◽  
Mimetic Peptides ◽  
Preglomerular Arterioles

Vascular conducted responses are believed to play a central role in controlling the microcirculatory blood flow. The responses most likely spread through gap junctions in the vascular wall. At present, four different connexins (Cx) have been detected in the renal vasculature, but their role in transmission of conducted vasoconstrictor signals in the preglomerular arterioles is unknown. Connexin mimetic peptides were previously reported to target and inhibit specific connexins. We, therefore, investigated whether conducted vasoconstriction in isolated renal arterioles could be blocked by the use of mimetic peptides directed against one or more connexins. Preglomerular resistance vessels were microdissected from kidneys of Sprague-Dawley rats and loaded with fura 2. The vessels were stimulated locally by applying electrical current through a micropipette, and the conducted calcium response was measured 500 μm from the site of stimulation. Application of connexin mimetic peptides directed against Cx40, 37/43, 45, or a cocktail with equimolar amounts of each, did not inhibit the propagated response, whereas the nonselective gap junction uncoupler carbenoxolone completely abolished the propagated response. However, the connexin mimetic peptides were able to reduce dye coupling between rat aorta endothelial cells shown to express primarily Cx40. In conclusion, we did not observe any attenuating effects on conducted calcium responses in isolated rat interlobular arteries when exposed to connexin mimetic peptides directed against Cx40, 37/43, or 45. Further studies are needed to determine whether conducted vasoconstriction is mediated via previously undescribed pathways.

scholarly journals Sodium, potassium and chloride utilization by rats given various inorganic anions

1991 ◽  
Vol 66 (3) ◽  
pp. 523-532 ◽  
Author(s):  
Susan M. Kaup ◽  
Alison R. Behling ◽  
J. L. Greger
Keyword(s):  
Blood Pressure ◽  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Basal Diet ◽  
Renin Activity ◽  
Sprague Dawley ◽  
Sodium Potassium ◽  
Sprague Dawley Rats ◽  
Blood Pressures ◽  
Sodium And Potassium

The purpose of the present studies was to examine the effect of ingestion of sodium and potassium salts of various fixed anions on blood pressure, and to assess interactions among electrolytes. In the first study, Sprague-Dawley rats fed on purified diets supplemented with Na salts of chloride, sulphate, bisulphate, carbonate and bicarbonate for 7 weeks developed higher blood pressures than rats fed on the basal diet. In a second study, rats fed on Na or K salts of HSO4, HCO3 or Cl had higher blood pressures than rats fed on the basal diet. Blood pressure measurements were not correlated with plasma volume, plasma renin activity, or plasma atrial natriuretic peptide concentrations at 7 weeks. Plasma renin activity was depressed in rats fed on supplemental Na and even more in rats fed on supplemental K salts rather than the basal diet. Generally, rats fed on supplemental Na excreted Na in urine and absorbed Na in the gut more efficiently than rats fed on the basal diet or diets supplemented with K, but the anions fed also altered Na absorption and excretion. In a third study, rats fed on diets supplemented with any Cl salt, but especially KCI, absorbed K more efficiently than those fed on the basal diet. In studies 1 and 2, the efficiency of urinary excretion of K was greatest when HCO3 and CO3 salts were fed and least when HSO4 salts were fed. Despite large variations in the efficiency of absorption and excretion of Na and K, tissue levels of the electrolytes remained constant.

Effect of high-salt diet on NO release and superoxide production in rat aorta

2004 ◽  
Vol 286 (2) ◽  
pp. H575-H583 ◽  
Author(s):  
Jiaxuan Zhu ◽  
Takefumi Mori ◽  
Tianjian Huang ◽  
Julian H. Lombard
Keyword(s):  
Rat Aorta ◽  
High Salt ◽  
Superoxide Production ◽  
Fluorescence Signal ◽  
Sprague Dawley ◽  
High Salt Diet ◽  
Salt Diet ◽  
Sprague Dawley Rats ◽  
Low Salt ◽  
No Release

Sprague-Dawley rats were fed either a high-salt (HS) diet (4.0% NaCl) or a low-salt (LS) diet (0.4% NaCl) for 3 days. Nitric oxide (NO) and superoxide production were assessed in the thoracic aorta by evaluating the fluorescence signal intensity from 4,5-diaminofluorescein (DAF-2DA) and dihydroethidine, respectively. Methacholine caused increased NO release in the aortas from rats on a LS but not HS diet. The SOD mimetic tempol restored methacholine-induced NO release in aortas from rats on a HS diet. Methacholine also caused superoxide production in the aortas of rats on a HS diet but not in the aortas of rats on a LS diet. Tempol and NG-monomethyl-l-arginine eliminated methacholine-induced superoxide production in the aortas of rats on a HS diet. Aortic rings from rats on the HS diet showed impaired methacholine-induced relaxation, which was improved by tempol. Tempol alone caused a NO-dependent relaxation of norepinephrine-precontracted aortas that was significantly greater in the aortas of rats on the HS diet than in vessels from rats on the LS diet. These data suggest that a HS diet impairs endothelium-dependent relaxation via reduced NO levels and increased superoxide production.

scholarly journals Sexual dimorphism in prostanoid-potentiated vascular contraction: roles of endothelium and ovarian steroids

2002 ◽  
Vol 283 (5) ◽  
pp. H2062-H2073 ◽  
Author(s):  
Clifford T. Fulton ◽  
John N. Stallone
Keyword(s):  
Sexual Dimorphism ◽  
Vascular Reactivity ◽  
Contractile Response ◽  
Rat Aorta ◽  
Maximal Response ◽  
Sprague Dawley ◽  
Similar Extent ◽  
Contractile Responses ◽  
Ovarian Steroids ◽  
Sprague Dawley Rats

The effects of constrictor prostanoid (CP) pathway inhibitors on vascular reactivity to vasopressin (VP) and phenylephrine (PE) were examined in thoracic aortas of male, female, and ovariectomized (OVX) female Sprague-Dawley rats. Maximal contractile response of control (Cont) aortas to VP was markedly higher in females (3,885 ± 332 mg/mg ring wt) than in males (810 ± 148 mg). Indomethacin (Indo; 10 μM) attenuated maximal response to VP in females (3,043 ± 277 mg) but not in males. SQ-29,548 (SQ; 1 μM) attenuated maximal response to VP in females (3,042 ± 290 mg) to a similar extent as Indo. Dazoxiben (Daz; 10 μM) alone had no effect, but Daz + SQ attenuated maximal contractile response to VP to a similar extent as SQ alone. Removal of the endothelium in female aortas attenuated contractile responses to VP in Cont aortas. OVX attenuated maximal contractile response to VP in Cont aortas (2,093 ± 329 mg) and abolished the attenuating effects of Indo. Indo, SQ, and Daz exerted identical effects on contractile responses of male, female, and OVX female aortas to PE. These findings establish the following in the rat aorta: 1) CP, probably thromboxane and/or endoperoxide, is responsible for ∼25–30% of contractile responses of females, but not males, to VP and PE; 2) CP production by the female aorta is primarily endothelial in origin; and 3) ovarian steroids modulate production and/or actions of CP in female aortas.

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