• The Korean Journal of Physiology
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• v.19 no.2
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• pp.189-202
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• 1985

Enhanced activity of renin-angiotensin-aldosterone system has been suggested as a cause of the high blood pressure in certain forms of experimental hypertension. In spontaneously hypertensive rats, however, increased activity of the system has not been found, and even suppressed renin angiotensin system has been reported in the spontaneously hypertensive rat. In the present experiments it was attempted to explore the possible alteration of the short loop negative feedback control in the hypertensive rat. Experiments have been done in the anesthetized spontaneously hypertensive rats(SHR) as well as in normotensive Wistar and Sprague Dawley rats as control. Responses of the plasma renin activity to the intravenous L-isoproterenol were dose dependent, in both SHR and normotensive control rats. Hypotensive responses to smaller do sea of L-isoproterenol were more accentuated in SHR than in the normotensive control rats. Angiotensin If given intravenously suppressed plasma renin activity in a dose dependent fashion in both groups. However, these suppressive responses were significantly attenuated in SHR as compared with the normotensive control rats. Treatment with angiotensin I-converting enzyme inhibitor did not correct the attenuated responses of the plasma renin activity to angiotensin II in SHR. Intravenous infusion of arginine vasopressin also produced a dose-dependent suppression of plasma renin activity in both groups. The responses to arginine vasopressin were also significantly attenuated to the normotensive control rats. In the sodium-depleted SHR, arginine vasopressin did not suppress plasma renin activity, whereas the suppressive responses to arginine vasopressin in the normotensive control rats were not different from the untreated control rats. These data suggest that there may be a derangement in the short loop negative feedback control of the renin-angiotensin system in spontaneously hypertensive rat.

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.27-31
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• 2000

The aim of this study was to investigate a potential effect of treatment of spontaneously hypertensive rats (SHR) with Pini Folium or Leonuri Herba extracts. Male SHR were treated with extracts for 2 or 4 weeks starting at 13 weeks of age. We found that oral treatment with the methanol extract from Pini Folium or Leonuri Herba (1g/Kg/day) significantly decreased mean blood pressure to 85.4% and 78.6% respectively in compare with untreated control SHR. Treatment with the extract from Pini Folium for 4 weeks during hypertension development phase (starting 9 weeks of age) resulted in a partial prevention of hypertension development. There were no significant differences for body weight between untreated and Pini Folium treated SHR.

• Archives of Pharmacal Research
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• v.16 no.4
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• pp.305-311
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• 1993

$Na^+,K^+$-ATPase activity, $Na^+$-dependent phosphorylation, and $[^3H]$ ouabain binding in sarcolemma prepared from 4 week old spontaneously hypertensive rat(SHR) ventricles were compared to the same parameters in sarcolemma from age matched nomotensive Wister-Kyoto (WKY) rat ventricles to examine whether the reduced myocardial $Na^+$-pump activity in SHR is an inherited enzymatic defect or a second phenomenon due to sustained hypertension. The total body weights, ventricular weights, and blood pressures were the same for SHR and WKY. No significant differences in sarcolemmal protein content and protein recovery were noted between the two groups. Sarcolemma isolated from SHR ventricles showed significantly less $Na^+,K^+$-ATPase activity ande number of phosphorylation sites when compared to sarcolemma from the WKY ventricles. Equilibrium binding of $[^3H]$ouabain and the tumover number of myocardial $Na^+,K^+$-ATPase, however, were the same for both groups. These reults indicate that the low affinity $(\alpha,\;or\;\alpha^1)\;\alpha$ isoform is the same in ventricles of SHR and WKY. The reduced amount of isoform of the $Na^+,K^+$-ATPase inprehypetensive SHR ventricles may play some role in the development of hypertension.

• Journal of Nutrition and Health
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• v.37 no.7
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• pp.509-514
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• 2004

This study was conducted to investigate the supplementary effects of Lentinus edodes on blood pressure and blood lipid levels in the Hypertensive Rat. We supplied 3 kinds of experimental diets (Control; CO, cap of Lentinus edodes; LC, and stipe of Lentinus edodes; LS) to spontaneously hypertensive rats (SHR) for 8 weeks. Diet intake, body weight, organ weights, and serum lipid levels were measured. There was no significant difference in diet intake, and body, liver and epididymal fat pad weights among experimental groups. The levels of systolic and diastolic blood pressure were significantly lower in LC and LS groups than CO group. The concentrations of serum total cholesterol were lower in LC and LS groups than CO group. These results suggested that Lentinus edodes decrease blood pressure levels and serum total cholesterol concentration in the spontaneously hypertensive rats. But these effects of Lentinus edodes didn't show any significant difference between animals fed cap and stipe of this mushroom.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.1
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• pp.243-249
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• 2004

KBPT is the fortified prescription of Bang-pung-tong-sung-san(BPTS) by adding Spatholobi Clulis and Salviae Miltiorrzae Radix. BPTS prescription has been utilized in oriental medicine for the treatments of vascular diseases including hypertension, stroke, and arteriosclerosis. Yet, the overall mechanism underlying its activity at the cellular levels remains unknown. Using spontaneously hypertensive rat (SHR) model, we investigated whether the KBPTS has an effect on the pathophysiological parameters related to hypertension. Pretreatment of SHR with KBPTS was found to lower blood pressure and heartbeat rate. Levels of aldosterone. dopamine, and epinephrine were found to be significantly reduced in the serum of KBPTS-treated SHR. Histological examination of adrenal cortex and superior aorta showed that tissues from KBPTS-treated SHR rats were more intact and cleaner compared to saline-treated control. Levels of superoxide dismutase (SOD) protein in adrenal gland, aorta, myocardial tissue, and kidneys were higher in KBPTS-treated animals than control group. The present data suggest that KBPTS may play a role in normalizing cardiovascular function in SHR by controlling hypertension-related blood factors and superoxide stressors.

• Archives of Pharmacal Research
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• v.11 no.4
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• pp.301-307
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• 1988

Relationship between the maintenance of hypertension and central serotonergic nervous system activity in opontaneously hypertensive rats (SHR) was studied. Serotonin turnover-rates were measured in 5 brain areas as an index of serotonergic neuronal activity and compared at the ages of 14 weeks in two types of animals; (1) spontaneously hypertensive rats (SHR) (2) normotensive wistar kyoto rats (WKY). In 14-week old SHR, central serotonin turnover rate was significantly lower in telencephalon, hypothalamus/thalamus and midbrain than normotensive rat, but significantly higher in cerebellum. There were no significant differences between serotonin turnover rate in pons/medulla of SHR and that of normotensive rat. THese data suggest that the abnormally lower turnover rates of serotonin in telencephalon, hypothalamus/thalamus and midbrain may be one of the underlying neuronal factors for manifestation of hypertension in SHR.

• The Korean Journal of Physiology
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• v.22 no.1
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• pp.41-53
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• 1988

The present study was undertaken to clarify the involvement of atrial natriuretic peptide in the development of hypertension in spontaneously hypertensive rats. Plasma concentration of immunoreactive atrial natriuretic peptide was higher in spontaneously hypertensive rats than in normotensive Sprague-Dawley and Wistar rats. Plasma renin concentration was lower in SHR than in normotensive rats, as observed in earlier experiments. Hydration-induced increase in urine flow and urinary excretions of sodium and potassium were smaller in SHR than in normotensive control rats. Intraarterial infusion of atrial natriuretic peptide resulted in increases in urine flow, urinary excretions of sodium and potassium in both hypertensive and normotensive rats. Renal response to atrial natriuretic peptide was markedly suppressed in SHR. Plasma renin and aldosterone concentration were suppressed by atrial natriuretic peptide in both SHR and normotensive rats. The responses were not significantly different in both groups. These results suggest that the renal responsiveness to atrial natriuretic peptide may be suppressed in SHR by some mechanisms still remaining obscure.

• Proceedings of the Ginseng society Conference
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• 1980.09a
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• pp.1-3
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• 1980

To investigate the effect of ginseng on blood pressure (B.P.) in spontaneously hypertensive rat (SHR) and essential hypertension ginseng extract was given per se daily in 58 SHR and 35 essential hypertensive patients. SHR were divided into 5 groups according to the dosage of ginseng. In essential hypertension 1,000mg of ginseng extract was given. The B.P. in SHR was measured by tail cuff method. In essential hypertension side effect and changes in various laboratory examinations were evaluated. In SHR ginseng appeared to have hypertensive effect when it is given in small amount(10mg/kg). However, when it is given 60mg/kg/day or more difinite B.P. lowering effect was observed. The hypotensive effect was dosedependant and it lasted for 37days of observation. In essential hypertension in 12 $(80\%)$ among 15 patients hypotensive effect was seen with ginseng administration along and the effect lasted for 12 weeks. In the rest of hypertensive patients it is required addition of diuretics of other antihypertensive drugs to decrease B.P., no appreciable side effect was seen. In laboratory examinations no significant changes were seen except for serum cholesterol, ${\alpha}-and\;{\beta}-lipoprotein,$ and hematocrit. There was some evidence of relationship between plasma renin activity (PRA) and ginseng in hypotensive action.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.291-296
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• 1987

There have been reports on the aberration of the control mechanisms of the blood pressure, hormone secretion, and renal functions in spontaneously hypertensive rats (SHR). However, the contribution of the renin-angiotensin system in the maintenance of high blood pressure in SHR is still controversial. Recently, it has been reported that the negative feedback short loop control mechanism of the renin-angiotensin system may be changed in SHR. In the present experiment, it was attempted to explore the possible alterations in the effect of arginine vasopressin (AVP) on the renal function in SHR. Experiments have been done in anesthetized SHR as well as in normotensive Wistar and Sprague-Dawley rats as control groups. Pharmacologic doses of AVP (10-13 mU/rat/10 min) decreased urine volume, excreted amount of creatinine and para-amino-hippuric acid. No differences in these parameters was observed between normotensive and hypertensive rats. AVP increased sodium and potassium excretion, but the responses in SHR were suppressed as compared with normotensive rats. Intravenous infusion of AVP also increased blood pressure in normotensive and hypertensive rats and a vasopressor effect of AVP was attenuated in SHR. There was a positive correlation between the changes in blood pressure and excreted amount of sodium during AVP infusion. These data suggest that the attenuated natriuretic effect of intravenous infusion of AVP may be due to a difference in renal tubular responsiveness to AVP but not due to a difference in vasopressor responsiveness.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.226-230
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• 1999

We have isolated a sesquiterpene lactone, cumambrin A from the dried flowers of Chrysanthemum boreale Makino and reported its chemical structure. The aim of the present study was to investigate whether the exogenous administration of cumambrin A has a pharmacological effect on normalization of blood pressure in the spontaneously hypertensive rats (SHR). In vitro studies: Relaxative response induced by cumainbrin A was increased with dose-dependent manner and showed maximizing response at a concentration of $5{\times}10^{-4}M$. Further, this relaxative response was significantly increased at a condition of endothelium present than that of endothelium denuded. In vivo studies: The normalizing effect of cumambrin A on blood pressure was also increased with time-dependent manner and then gradually recovered to normal condition at approximately 4 hrs after cumambrin A treatment.