Effects of sodium chloride on early and chronic phases of malignant hypertension in rats

1979 ◽  
Vol 236 (5) ◽  
pp. H665-H671
Author(s):  
J. M. Rojo-Ortega ◽  
F. P. Queiroz ◽  
J. Genest

Malignant hypertension was induced in Sprague-Dawley rats by a complete aortic ligation above the left renal artery. The effects of saline (0.9% NaCl) administration on the development and course of the malignant hypertensive vascular disease were studied and the treated rats were compared to non-saline-treated animals and to sham-operated controls in the early and chronic phases of the disease. In the early phase, blood pressure, hematocrit, body weight, and hypertensive vascular disease were characteristic of the malignant hypertensive process and were without significant difference in saline- and non-saline-treated animals. In contrast, the sham-operated rats remained normotensive and did not present abnormal histological findings. Plasma renin activity although decreased in the hypertensive saline-treated animals was not suppressed. In the chronic phase, NaCl administration caused an average increase of 40 g body weight during the 1-wk period this solution was given, but did not result in any improvement in blood pressure levels and vascular disease in treated rats compared to non-saline-treated animals.

1988 ◽  
Vol 255 (6) ◽  
pp. E839-E842
Author(s):  
M. Chen ◽  
J. G. Lee ◽  
R. L. Malvin ◽  
B. S. Huang

The present experiments were designed to determine if an opiate antagonist affects blood pressure in two-kidney one-clip Goldblatt rats. Male Sprague-Dawley rats were divided into three groups. Group 1 received an infusion of saline intraperitoneally via an osmotic pump and left renal artery constriction (RAC). In group 2, rats were treated the same as group 1, except that they received an intraperitoneal infusion of naloxone (100 micrograms/h). Group 3 received the same infusion of naloxone without RAC. Naloxone-infused Goldblatt rats showed a significantly lower systolic blood pressure (SBP) than saline-infused Goldblatt rats (132 +/- 7 vs. 160 +/- 9 mmHg at day 14), but a higher SBP than control (132 +/- 7 vs. 106 +/- 1 mmHg). Infusion of naloxone did not significantly change SBP in normotensive rats. Renal renin activity in the clipped kidney was higher than in the nonclipped kidney in groups 1 and 2. Plasma renin activity (PRA) in both groups of Goldblatt rats was higher than in group 3, but no significant difference was found between the two groups of Goldblatt rats (groups 1 and 2). Naloxone (1.5 microM) did not affect the basal secretion of renin by isolated cortical slices from untreated rats. The present data demonstrate that naloxone significantly attenuates the development of hypertension in two-kidney one-clip rats. The attenuation of blood pressure was not associated with the changes in PRA, renal renin activity, or plasma aldosterone concentrations. The data support the hypothesis that the endogenous opioid system may be involved in the development of renovascular hypertension.


2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Kwan Yuet Ping ◽  
Ibrahim Darah ◽  
Yeng Chen ◽  
Subramaniam Sreeramanan ◽  
Sreenivasan Sasidharan

DespiteEuphorbia hirtaL. ethnomedicinal benefits, very few studies have described the potential toxicity. The aim of the present study was to evaluate thein vivotoxicity of methanolic extracts ofE. hirta. The acute and subchronic oral toxicity ofE. hirtawas evaluated in Sprague Dawley rats. The extract at a single dose of 5000 mg/kg did not produce treatment related signs of toxicity or mortality in any of the animals tested during the 14-day observation period. Therefore, the LD 50 of this plant was estimated to be more than 5000 mg/kg. In the repeated dose 90-day oral toxicity study, the administration of 50 mg/kg, 250 mg/kg, and 1000 mg/kg/day ofE. hirtaextract per body weight revealed no significant difference (P>0.05) in food and water consumptions, body weight change, haematological and biochemical parameters, relative organ weights, and gross findings compared to the control group. Macropathology and histopathology examinations of all organs including the liver did not reveal morphological alteration. Analyses of these results with the information of signs, behaviour, and health monitoring could lead to the conclusion that the long-term oral administration ofE. hirtaextract for 90 days does not cause sub-chronic toxicity.


2006 ◽  
Vol 231 (3) ◽  
pp. 282-287 ◽  
Author(s):  
Anita D. Smith ◽  
Michael W. Brands ◽  
Mong-Heng Wang ◽  
Anne M. Dorrance

A correlation exists between obesity and hypertension. In the currently available models of diet-induced obesity, the treatment of rats with a high fat (HF) diet does not begin until adulthood. Our aim was to develop and characterize a model of pre-pubescent obesity-induced hypertension. Male Sprague-Dawley rats were fed a HF diet (35% fat) for 10 weeks, beginning at age 3 weeks. Blood pressure was measured by tail-cuff, and a terminal blood sample was obtained to measure fasting blood glucose, insulin, plasma renin, aldosterone, thiobarbitutic acid reactive substances (TBARS), and free 8-isoprostanes levels. The vascular reactivity in the aorta was assessed using a myograph. Blood pressure was increased in rats fed the HF diet (HF, 161 ± 2 mm Hg vs. control, 137 ± 2 mm Hg, P < 0.05). Blood glucose (HF, 155 ± 4 mg/dL vs. control, 123 ± 5 mg/dL, P < 0.05), insulin (HF, 232 ± 63 pM vs. control, 60 ± 11 pM, P < 0.05), TBARS (expressed as nM of malondialdehyde [MDA]/ml [HF, 1.8 ± 0.37 nM MDA/ml vs. control 1.05 ± 0.09 nM MDA/ml, P < 0.05]), and free 8-isoprostanes (HF, 229 ± 68 pg/ml vs. control, 112 ± 9 pg/ml, P < 0.05) levels were elevated in the HF diet group. Interestingly, plasma renin and aldosterone levels were not different between the groups. The maximum vasoconstriction to phenylephrine (10−4 M) was increased in the HF diet group (HF, 26.1 ± 1.5 mN vs. control 22.3 ± 1.2 mN, P < 0.05). In conclusion, pre-pubescent rats become hypertensive and have increased oxidative stress and enhanced vasoconstriction when fed a HF diet. Surprisingly, this occurs without the increase in renin or aldosterone levels seen in the adult models of diet-induced obesity.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Yukiko Segawa ◽  
Hiroko Hashimoto ◽  
Saki Maruyama ◽  
Tomoko Osera ◽  
Nobutaka Kurihara

Objective: Saccharina japonica (SJ), one of brown algae, is cultivated or grows wild in Japan and neighbor countries. The extract “dashi” is used for soup stock in Japan. We reported the decreases in blood pressure (BP) both by the intake of SJ diet and by dashi extracted from SJ (DASHI) in 2-kidney, 1-clip renovascular hypertensive (2K1C) rats. Some researchers have suggested that alginic acid (AA) may be involved in the mechanism of the SJ effect. However, DASHI contains AA as much as 5%(5 of 100) of what the original SJ contains. Thus, the antihypertensive effects by SJ in 2K1C may be through the other contents of SJ. SJ is rich in Glutamic acid (GA) which is one of the umami, the intake of which was reported to decrease BP in human in epidemiologic studies. GA is eluted from the SJ into the DASHI when extracting DASHI from SJ. Therefore, we hypothesized that GA in DASHI contributes to the mechanism of BP decreased by DASHI diet in 2K1C rats. In this study, we observed BP in 2K1C rats fed a diet containing GA as much as that in the SJ diet which had decreased BP in the previous study. Methods: Male Sprague-Dawley rats (6wks) were treated with sham operation (SHAM) or clipping the left renal artery (2K1C). After surgery, the rats started receiving a control diet (C) or a diet containing L-GA (G) for 6 weeks. The systolic BP (SBP) was measured by a tail-cuff method every week. At the end, mean arterial BP (MAP) was measured in each rat under anesthesia. Result: Six weeks after the surgery, SBP was significantly higher in 2K1C-C than in SHAM-C (163±2 vs 111±5 mmHg, p<0.05). In 2K1C-G (171±7), it showed no significant difference compared with 2K1C-C and was significantly higher than that in SHAM-C (p<0.05). At the end of the protocol, MAP showed the similar results to SBP. Conclusion: Glutamic acid may not contribute to the mechanism of alleviating hypertension by dietary SJ and SJ extract in 2K1C.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Ana C Palei ◽  
Eric M George ◽  
Marietta Arany ◽  
Kathy Cockrell ◽  
Joey P Granger

While the relationship of obesity to cardiovascular disease is well recognized, it also has important implications for pregnancy outcomes. Indeed, there is compelling evidence that obesity increases the risk of preeclampsia (PE). The risk of severe and mild PE and PE occurring in early and late gestation are greater in obese and overweight women. Despite the fact that obesity is the leading attributable risk for PE in developed countries, the pathophysiological mechanisms whereby obesity and metabolic factors such as leptin increases the risk for developing PE are unclear. Hyperleptinemia over the levels seen in normal pregnancy has been associated with preeclampsia. Thus the aim of this study was to investigate whether chronic hyperleptinemia causes changes in cardiovascular, metabolic and reproductive systems of pregnant rats. On gestational day (GD) 14, Sprague Dawley rats were assigned to normal pregnant (NP, n=8) group or to NP plus Leptin group (NP+Lep, n=8), in which miniosmotic pump with leptin (0.5 μg/kg/min) was placed intraperitoneally. On GD 19, mean arterial pressure (MAP) was recorded, rats were sacrificed, and blood, placentas and pups were collected. Body weight (BW) and food intake (FI) were measured on GD 16-18. Serum leptin concentration was elevated in NP+Lep compared with NP (0.82 ± 0.05 vs 17.98 ± 2.75 ng/mL, P<0.05). Circulating insulin and glucose levels were similar in NP and NP+Lep groups (both P>0.05). MAP was higher in NP+Lep compared with NP (102.40 ± 2.38 vs 121.30 ± 8.13 mmHg, P<0.05). BW was decreased in NP+Lep compared with NP at GD 19 (330.90 ± 9.08 vs 284.10 ± 8.58 g, P<0.05), probably due to the reduced FI of the NP+Ins group compared with NP during GD 16-18 (23.45 ± 0.61 vs 8.61 ± 0.83 g/day, P<0.05). Although the number of viable fetuses per rat was similar between groups (P>0.05), fetuses and placentas of the NP+Lep group were lighter than those of the NP group (2.29 ± 0.06 vs 2.11 ± 0.06 g and 0.58 ± 0.01 vs 0.50 ± 0.02 g, respectively, both P<0.05). In conclusion, leptin increases blood pressure, despite its effect of reducing body weight during pregnancy, representing a possible mechanism to induce hypertension in preeclampsia. In addition, leptin decreases pup and placental weights, which could lead to abnormal fetal outcomes.


1991 ◽  
Vol 66 (3) ◽  
pp. 523-532 ◽  
Author(s):  
Susan M. Kaup ◽  
Alison R. Behling ◽  
J. L. Greger

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.


2003 ◽  
Vol 105 (2) ◽  
pp. 235-242 ◽  
Author(s):  
Rhian M. TOUYZ ◽  
Guoying YAO

In the present in vivo study, we have investigated whether inhibitors of the Na+/Mg2+ exchanger quinidine and imipramine influence the development of hypertension and whether this is associated with modulation of mitogen-activated protein (MAP) kinase activation in arteries and kidneys of hypertensive rats. Sprague—Dawley rats were divided into four groups (n=6/group): control (vehicle), angiotensin II (Ang II; 150 ng/kg of body weight per min subcutaneously), quinidine [Ang II (150 ng/kg of body weight per min)+quinidine (5 mg/kg of body weight per day in food)] and imipramine groups [Ang II (150 ng/kg of body weight per min)+imipramine (5 mg/kg/day in food)]. Rats were studied for 3 weeks. Phosphorylation of vascular and renal extracellular-signal-regulated protein kinase 1/2 (ERK1/2), p38MAP kinase and c-Jun N-terminal kinase (JNK) were assessed using phospho-specific antibodies. Ang II increased systolic blood pressure from 112±5 mmHg to 215±9 mmHg (P<0.01). Development of hypertension was attenuated in Ang II-infused rats treated with quinidine (173±6 mmHg) and imipramine (152±6 mmHg) (P<0.01). Phosphorylation of ERK1/2, p38MAP kinase and JNK, which were increased 2–3-fold in arteries of the Ang II group, were reduced by quinidine and imipramine (P<0.05). Activation of renal MAP kinases was also increased in the Ang II group (P<0.05). Quinidine and imipramine reduced the phosphorylation of renal ERK1/2, but did not modify renal p38MAP kinase or JNK. Our data demonstrate that Ang II induces severe hypertension in Sprague—Dawley rats and this is associated with increased phosphorylation of vascular and renal MAP kinases. Quinidine and imipramine attenuated the development of hypertension and normalized MAP kinase activity. The findings from this study suggest a possible role for the Na+/Mg2+ exchanger in vascular signalling events associated with blood pressure elevation in Ang II-dependent hypertension.


2015 ◽  
Vol 17 (2) ◽  
pp. 118
Author(s):  
Sri Isdadiyanto

The objective of this study was to analyze the ratio of LDL/HDL level of Sprague Dawley rats induced by high fat ration after given of sea shrimp carapace (Penaeus monodon F.). The animals for this study were twenty adult male rats divided into four groups, i.e. group I as the control was fed with basal ration containing normal fat for 3 months, group II was fed ration containing high fat for 3 months, group III was fed ration containing high fat and given sea shrimp carapace 180 mg per kg body weight per day orally in 2 ml aquadest for 3 months, group IV was fed ration containing high fat for 3 months and after 1 month given sea shrimp carapace 180 mg per kg body weight per day orally in 2 ml aquadest for 2 months. Each group consisted of five animals. After 90 days, the rats were necropsied and the blood were collected to analyzes ratio of LDL/HDL level. LDL level and HDL level were measured using colorimetric enzymatic method and Roche/Hitachi cobas c systems automatically calculate.  The difference between treatments was statistical analysis by Anava, and continued by Lowest Significant Difference Test to locate the difference. The result showed that high fat diet increased ratio of LDL/HDL level and Sea shrimp carapace decreased ratio of LDL/HDL level.   Keywords: Sea shrimp carapace, Sprague Dawley rats, ratio of LDL/HDL level


1998 ◽  
Vol 95 (4) ◽  
pp. 445-451 ◽  
Author(s):  
Rachel OKUNIEWSKI ◽  
Elizabeth A. DAVIS ◽  
Bevyn JARROTT ◽  
Robert E. WIDDOP

1.The objective of this study was to determine the influence of gender on the development of renal hypertension in Sprague–Dawley rats using the Goldblatt two-kidney, one-clip (2K1C) model. In addition, this study examined the effect of ovariectomy upon the development of hypertension in female rats. 2.At 10 weeks of age, male, intact female and ovariectomized female rats underwent clipping of the right renal artery or sham operation. Tail-cuff plethysmography was used to monitor the systolic blood pressure of all animals for 7 weeks post-clipping or sham operation. Rats were sub-grouped according to whether or not they developed hypertension (systolic blood pressure ⩾ 150 ;mmHg). 3.Within 2 to 3 weeks of clipping, hypertension was induced in only 53% (n = 120) of the intact female 2K1C rats, but in 83% (n = 18) of the male and 78% (n = 18) of the ovariectomized female rats. 4.Seven weeks after right renal artery clipping, plasma renin activity was determined in a subset of each group and was found to be 5–6 fold higher in male (17.29±4.04 ;ng angiotensin I·h-1·ml-1) and ovariectomized female (9.71±1.25 ;ng angiotensin I·h-1·ml-1) hypertensive rats compared with their respective normotensive or sham-operated counterparts (3.39±0.58 ;ng angiotensin I·h-1·ml-1 and 1.60±0.41 ;ng angiotensin I·h-1·ml-1 respectively) (P< 0.05, analysis of variance). In contrast, the plasma renin activity measured in intact female hypertensive rats was not significantly different from that measured in the corresponding 2K1C normotensive or sham-operated groups. 5.These results indicate that the success rate of inducing renal hypertension in Sprague–Dawley rats is higher in males than in intact females. Furthermore, these results suggest that the induction of 2K1C hypertension may be influenced by ovarian hormones.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Saki Maruyama ◽  
Yukiko Segawa ◽  
Hiroko Hashimoto ◽  
Tomoko Osera ◽  
Nobutaka Kurihara

Objective: One of foods indispensable to Japanese cuisine “Washoku” is algae, including Saccharina japonica (SJ) and Undaria pinnatifida. The intake of SJ is reported to decrease blood pressure (BP) in spontaneously hypertensive rats in some studies, and in 2-kidney, 1-clip hypertensive (2K1C) rats in our studies. Since SJ soaked in vinegar is often used in Japanese cuisine, we observed the effects of dietary intake of SJ soaked in vinegar on BP in 2K1C rats. Methods: Male Sprague-Dawley rats (6 wks) were treated with sham operation (SHAM) or clipping the left renal artery (2K1C). After surgery, the rats started receiving a control diet (C), a diet with 5.0% (w/w) SJ (S), or a diet with 5.0% SJ soaked in 5.0% (v/v) vinegar (SV). Systolic BP (SBP) was measured by a tail-cuff method every week for 6 weeks. At the end of the protocol, mean arterial BP (MAP) was measured in each rat under anesthesia. Results and Discussion: Analysis of variance shows that SBP was significantly higher in 2K1C-C than SHAM-C through the experimental period (P<0.001), and that SBP was lower in 2K1C-S (P<0.05) and -SV (P<0.001) than in 2K1C-C (Fig). It also demonstrated that 2K1C-SV provided a significant reduction in SBP compared with 2K1C-S (p<0.001). At the end of the protocol, MAP in 2K1C-C was significantly higher than SHAM-C (154±4 vs 141±4 mmHg, P<0.05). Compared with 2K1C-C, a significant reduction in MAP was observed not in 2K1C-S (143±2 mmHg) but in 2K1C-SV (133±4 mmHg, p<0.05). Soaking in vinegar might bring alginate, which is one of possible components playing an important role in decreasing BP by SJ, to a low molecule and enhance the effect. Conclusion: SJ soaked in vinegar may decrease BP more than SJ in 2K1C rats.


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