An antihypertensive extract of erythrocytes: effects on 45Ca uptake and efflux

1986 ◽  
Vol 64 (4) ◽  
pp. 424-429
Author(s):  
G. L. Wright ◽  
G. O. Rankin ◽  
W. D. McCumbee
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Calcium Uptake ◽  
Slow Component ◽  
Present Report ◽  
Calcium Stores ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Washout Curves

The present report describes some aspects of the effects of a recently described antihypertensive extract of erythrocytes (AHF) on calcium uptake and efflux in rat aortae. AHF was found to be present in the erythrocytes of both spontaneously hypertensive rats and normotensive rats. Furthermore, AHF obtained from erythrocytes of SH rats was shown to be equally effective in suppressing lanthanum-resistant calcium uptake in aortae from hypertensive and normotensive rats. AHF treatment prior to incubation of aortae with 45Ca caused an apparent increase in the total 45Ca uptake. The analysis of calcium washout curves obtained for tissue in calcium-free or lanthanum-containing media indicated that AHF had no significant effect on the rate of calcium loss from the slow component of efflux, though this compartment tended to be reduced in size. This indicated that the increase in the 45Ca content of AHF-exposed aortae prior to rinsing was confined to the rapid component of efflux. The loss of calcium from the rapidly exchanging compartment was enhanced in either of the efflux media used. The results suggest that a principal action of AHF involves an increase in the lability and exchangeability of calcium stores. In addition to its effects in resting tissue, AHF abolished the increase in lanthanum-resistant calcium uptake induced in rat aortae by the addition of high K+ or norepinephrine to the incubation media. In a second part of the study, the effect of AHF on blood pressure and in vitro calcium uptake were compared with that of phosphatidylethanolamine (PEA), the probable identity of another endogenous antihypertensive (renin preinhibitor) compound earlier shown to share important functional similarities with AHF. The results reduce the likelihood that the two causal agents are identical. The AHF produced a significant (75 Torr, 1 Torr = 133.32 Pa) fall in the systolic blood pressure (SBP) of spontaneously hypertensive rats within 24 h following injection, whereas PEA had no effect on the SBP in this model. Both AHF and PEA reduced the resting in vitro uptake of "lanthanum-resistant" calcium in rat aortic segments. However, the AHF effect was significantly greater than PEA at each concentration studied.

Solanum macrocarpon Leaf Extracts Reduced Blood Pressure and Heart Rate After Oral Administration to Spontaneously Hypertensive Rats

2019 ◽  
Vol 17 (3) ◽  
pp. 282-290 ◽  
Author(s):  
Olayinka A. Oluwagunwa ◽  
Adeola M. Alashi ◽  
Rotimi E. Aluko
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Leaf Extracts ◽  
Spontaneously Hypertensive ◽  
Vitro Analysis ◽  
Gallic Acid Equivalent ◽  
In Vitro Analysis

The aim of this work was to determine the ability of polyphenol-enriched aqueous vegetable leaf extracts to ameliorate blood pressure and heart rate dysfunctions in spontaneously hypertensive rats (SHRs). Solanum macrocarpon (SM), a common edible vegetable leaf in West Africa was cultivated using varying levels (0-80 kg/ha) of urea that was applied at planting (T1) or 2 weeks after planting (T2). In vitro analysis showed that total polyphenolic compounds varied from 489.87 ± 5.66 to 513.56 ± 1.42 mg gallic acid equivalent/g dry wt of extract. Rutin, caffeic acid and myricetin were the major polyphenols quantified in the extracts. All the extracts inhibited in vitro activities of renin and angiotensin converting enzyme to varying extents. Two extracts (SM40T1 and SM80T2) were orally administered to SHRs at 100 or 500 mg/kg body wt. Results showed that systolic blood pressure was reduced to a similar level by SM40T1 (10.8 mmHg) and SM80T2 (10.5 mmHg) for the 100 mg/kg body wt dose; the 500 mg/kg body wt dose produced similar values. Diastolic blood pressure and heart rate were also depressed by the two extracts with similar effects observed for both doses. We conclude that the leaf extracts could serve as potential ingredients to formulate antihypertensive functional foods and nutraceuticals.

Importance of the adrenal cortex for development and maintenance of hypertension in spontaneously hypertensive rats

1984 ◽  
Vol 105 (3) ◽  
pp. 417-424 ◽  
Author(s):  
W. Ruch ◽  
J. B. Baumann ◽  
A. Häusler ◽  
U. H. Otten ◽  
H. Siegl ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Adrenal Cortex ◽  
Spontaneously Hypertensive Rats ◽  
Age Groups ◽  
Plasma Corticosterone ◽  
Hypertensive Rats ◽  
Acth Stimulation ◽  
Spontaneously Hypertensive ◽  
Adrenal Steroid

Abstract. Adrenal regeneration following complete bilateral adrenalectomy in spontaneously hypertensive rats (SHR) was used to study the significance of glucocorticoid and mineralocorticoid hormones for the development and maintenance of hypertension. Pre-hypertensive (5 weeks of age) and hypertensive (10 and 16 weeks of age) male SHR underwent adrenalectomy (ADN) and were kept on 0.9% NaCl. The rats were ether stressed at various intervals to assess adrenal steroid production. Following ADN of all three age groups the development or maintenance of hypertension depended on the presence of adrenal regenerates. Animals without signs of adrenal regeneration remained or became normotensive. There was a significant correlation between plasma corticosterone levels following ether stress and blood pressure. Aldosterone and corticosterone production of regenerates and of adrenal cortex of intact SHR was studied in vitro. Under basal condition and following ACTH stimulation both tissues produced similar amounts of corticosterone, however considerably less aldosterone was secreted by regenerates. Betamethasone substitution in adrenalectomized rats caused a dramatic increase of blood pressure which was attenuated by l-propranolol. Aldosterone had no significant effect on blood pressure. It is concluded that glucocorticoids play a permissive role in the development of hypertension presumably via alteration of sympathetic neurotransmission.

An antihypertensive substance associated with erythrocytes

1985 ◽  
Vol 248 (4) ◽  
pp. H445-H451
Author(s):  
W. D. McCumbee ◽  
G. O. Rankin ◽  
G. L. Wright
Keyword(s):  
Blood Pressure ◽  
Phospholipase D ◽  
Calcium Uptake ◽  
Hypertensive Rats ◽  
Control Groups ◽  
Spontaneously Hypertensive ◽  
Calcium Effects ◽  
Triton X ◽  
Dose Dependent

An extract was prepared from hemolyzed erythrocytes of spontaneously hypertensive rats (SHR) which inhibits lanthanum-resistant calcium uptake by aortic segments and lowers blood pressure in several models of hypertension. Erythrocyte hemolysates were extracted with Triton X-100 and partially purified by boiling and Sephadex G-150 column chromatography. The effects of the extract on calcium uptake by aortic segments in vitro were reversible and dose dependent. The extract was administered by intraperitoneal injection to male and female SHR, deoxycorticosterone-NaCl hypertensive rats (DOCA-NaCl), one-kidney one-clip (1K,1C) and two-kidney, one-clip (2K,1C) renovascular hypertensive rats, and their appropriate control groups. At 24 h postinjection, the antihypertensive factor (AHF) lowered the systolic blood pressure (SBP) in the conscious SHR male (200 +/- 7 to 132 +/- 11 Torr), SHR female (172 +/- 4 to 117 +/- 11), DOCA-NaCl (187 +/- 6 to 121 +/- 8), 2K,1C (165 +/- 8 to 127 +/- 7), and 1K,1C (167 +/- 8 to 146 +/- 13) models of hypertension. The duration of the effect on the SBP was model dependent. The SBP was significantly decreased for 4-8 days in SHR, 4 days in 1K,1C and 2K,1C, and 2 days in DOCA-NaCl. In contrast to the results obtained in hypertensive rats, AHF had little effect on the SBP of normotensive animals. Both the blood pressure and calcium effects were abolished by digestion with phospholipase D, tentatively suggesting that the compound(s) inducing these effects may be a phospholipid or have a phospholipid moiety.

scholarly journals Administration with Quinoa Protein Reduces the Blood Pressure in Spontaneously Hypertensive Rats and Modifies the Fecal Microbiota

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2446
Author(s):  
Huimin Guo ◽  
Yuqiong Hao ◽  
Xin Fan ◽  
Aurore Richel ◽  
Nadia Everaert ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Alpha Diversity ◽  
Treated Group ◽  
Fecal Microbiota ◽  
Potential Candidate ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive

Despite the well-established role of quinoa protein as the source of antihypertensive peptides through in vitro enzymolysis, there is little evidence supporting the in vivo antihypertensive effect of intact quinoa protein. In this study, in vivo study on spontaneously hypertensive rats (SHRs) was conducted by administering quinoa protein for five weeks. Gastrointestinal content identification indicated that many promising precursors of bioactive peptides were released from quinoa protein under gastrointestinal processing. Quinoa protein administration on SHRs resulted in a significant decrease in blood pressure, a significant increase in alpha diversity, and microbial structure alternation towards that in non-hypertension rats. Furthermore, blood pressure was highly negatively correlated with the elevated abundance of genera in quinoa protein-treated SHRs, such as Turicibacter and Allobaculum. Interestingly, the fecal microbiota in quinoa protein-treated SHRs shared more features in the composition of genera with non-hypertension rats than that of the captopril-treated group. These results indicate that quinoa protein may serve as a potential candidate to lower blood pressure and ameliorate hypertension-related gut dysbiosis.

Stimulation of aortic tissue calcium uptake by an extract of spontaneously hypertensive rats erythrocytes possessing hypertensive properties

1986 ◽  
Vol 64 (12) ◽  
pp. 1515-1520 ◽  
Author(s):  
G. L. Wright ◽  
M. E. Rogerson ◽  
W. D. McCumbee
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Calcium Uptake ◽  
Vascular Tissue ◽  
Aortic Tissue ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
High K ◽  
Tissue Sensitivity ◽  
Tissue Calcium

In earlier reports we have described the isolation of a fraction from the erythrocytes of spontaneously hypertensive rats that produced hypertension when administered to normotensive rats. In addition, it was found that the fraction stimulated the uptake of "lanthanum-resistant" calcium by aortic rings excised from normotensive rats. In these studies we have found that the fraction causes a greater increase in the in vitro uptake of calcium by aortic tissue than that produced by depolarization of the tissue with high K+ or the receptor-mediated influx of calcium induced with norepinephrine. The hypertensive fraction appeared to be more effective in promoting increased calcium uptake in rabbit than in rat aortic tissue, suggesting that significant differences in tissue sensitivity to the active compound(s) may exist between species. In addition, we obtained evidence indicating that the tissue sensitivity to the action of the hypertensive fraction was greater in aortae from spontaneously hypertensive rats than from those of normotensive animals. Attempts to block the action of the hypertensive fraction with verapamil, nifedipine, and sodium nitroprusside had no significant effect on the elevation in tissue calcium. It was found, however, that the action of the hypertensive fraction was temperature dependent with reduced activity at lower temperatures. The data suggest that a compound(s) is present in the erythrocytes of rats that may have a marked effect on vascular tissue metabolism of calcium.

Increased Sodium Content and Altered Sodium Transport in Thymocytes of Spontaneously Hypertensive Rats

1981 ◽  
Vol 61 (3) ◽  
pp. 313-316 ◽  
Author(s):  
R. B. Jones ◽  
J. Patrick ◽  
P. J. Hilton
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Rate Constant ◽  
Spontaneously Hypertensive Rats ◽  
Sodium Content ◽  
Strong Positive Correlation ◽  
Hypertensive Rats ◽  
Sodium Efflux ◽  
Spontaneously Hypertensive

1. The intracellular sodium content and the sodium efflux rate constant have been determined in vitro in thymocytes derived from the Okamato-Aoki strain of spontaneously hypertensive rats. 2. A strong positive correlation between the systolic blood pressure and the sodium content of thymocytes was observed (r = 0.59, n = 39, P < 0.001). 3. The rate constant for total sodium efflux was negatively correlated with systolic blood pressure (r = −0.43, n = 45, P < 0.005) and this was due to a fall in the ouabain-sensitive component of sodium efflux. 4. Sodium efflux, influx and the thymocyte potassium content were not related to the blood pressure.

scholarly journals Antihypertensive effect of aqueous polyphenol extracts of Amaranthusviridis and Telfairiaoccidentalis leaves in spontaneously hypertensive rats

2018 ◽  
Vol 1 ◽  
Author(s):  
Olayinka A. Olarewaju ◽  
Adeola M. Alashi ◽  
Rotimi E Aluko
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Antihypertensive Agents ◽  
Hypertensive Rats ◽  
Leaf Extracts ◽  
Spontaneously Hypertensive ◽  
Angiotensin I Converting Enzyme ◽  
Arterial Blood ◽  
Renin Inhibition

The antihypertensive effects of aqueous polyphenol-rich extracts of Amaranthusviridis (AV) and Telfairiaoccidentalis (TO) leaves in spontaneously hypertensive rats (SHR) were investigated. The dried vegetable leaves were extracted using 1:20 (leaves:water, w/v) ratio for 4 h at 60 °C. Results showed significantly (P < 0.05) higher polyphenol contents in TO extracts (80–88 mg gallic acid equivalents, GAE/100 mg) when compared with the AV (62–67 mg GAE/100 mg). Caffeic acid, rutin and myricetin were the main polyphenols found in the extracts. The TO extracts had significantly (P < 0.05) higher in vitro inhibition of angiotensin I-converting enzyme (ACE) activity while AV extracts had better renin inhibition. Oral administration (100 mg/kg body weight) to SHR led to significant (P < 0.05) reductions in systolic blood pressure for the AV (−39 mmHg after 8 h)and TO (−24 mmHg after 4 and 8 h).The vegetable extracts also produced significant (P < 0.05) reductions in diastolic blood pressure, mean arterial blood pressure and heart rate when compared to the untreated rats. Thus both the AV and TO leaf extracts have the potential to be used as antihypertensive agents, especially the AV, which produced persistent long-lasting effect over a 24 h period.

scholarly journals Hypotensive and Angiotensin-Converting Enzyme Inhibitory Activities ofEisenia fetidaExtract in Spontaneously Hypertensive Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shumei Mao ◽  
Chengde Li
Keyword(s):  
Blood Pressure ◽  
Inhibitory Activity ◽  
Spontaneously Hypertensive Rats ◽  
Ang Ii ◽  
Shr Rats ◽  
Hypertensive Rats ◽  
Ace Inhibitory Activity ◽  
Spontaneously Hypertensive ◽  
Ace Inhibitory

Objectives. This study aimed to investigate the antihypertensive effects of anEisenia fetidaextract (EFE) and its possible mechanisms in spontaneously hypertensive rats (SHR rats).Methods. Sixteen-week-old SHR rats and Wistar-Kyoto rats (WKY rats) were used in this study. Rats were, respectively, given EFE (EFE group), captopril (captopril group), or phosphate-buffered saline (PBS) (normal control group and SHR group) for 4 weeks. ACE inhibitory activity of EFEin vitrowas determined. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a Rat Tail-Cuff Blood Pressure System. Levels of angiotensin II (Ang II), aldosterone (Ald), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α) in plasma were determined by radioimmunoassay, and serum nitric oxide (NO) concentration was measured by Griess reagent systems.Results. EFE had marked ACE inhibitory activityin vitro(IC50= 2.5 mg/mL). After the 4-week drug management, SHR rats in EFE group and in captopril group had lower SBP and DBP, lower levels of Ang II and Ald, and higher levels of 6-keto-PGF1αand NO than the SHR rats in SHR group.Conclusion. These results indicate that EFE has hypotensive effects in SHR rats and its effects might be associated with its ACE inhibitory activity.

Hypotensive Effects of Captopril, Saralasin and Bromocriptine in Spontaneously Hypertensive Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 79s-82s ◽  
Author(s):  
J. S. Hutchinson ◽  
A. E. Doyle
Keyword(s):  
Blood Pressure ◽  
Dopamine Agonist ◽  
Intravenous Injection ◽  
Spontaneously Hypertensive Rats ◽  
Spontaneously Hypertensive Rat ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Dose Dependent

1. Neurosecretion of peptides from superfused neurohypophyses in vitro was inhibited by dopamine. 2. This inhibition was dose-dependent. 3. Intravenous injection of the dopamine agonist, bromocriptine, lowered blood pressure in spontaneously hypertensive rats within 15 min. 4. Saralasin or captopril also lowered blood pressure of spontaneously hypertensive rats, but progressively over a period of 3 h. 5. The results suggest that dopamine and angiotensin have opposite effects on the neurosecretion of vasopressin. 6. Vasopressin appears to be involved in maintenance of blood pressure in the spontaneously hypertensive rat but is apparently not the only factor.

Sign in / Sign up

Export Citation Format

Share Document