• Title/Summary/Keyword: SHR

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The Effects of Exercise Training on Cardiac eNOS, ET-1 mRNA and Skeletal Muscle eNOS Protein Level in SHR (지구성 운동이 본태성 고혈압 쥐 심장근의 eNOS, ET-1 mRNA와 골격근 eNOS 단백질 발현에 미치는 영향)

  • Song, Eun-Young;Cho, In-Ho;Cho, Joon-Yong
    • Journal of Life Science
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    • v.17 no.12
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    • pp.1717-1722
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    • 2007
  • In the present study, all of the treadmill exercise-trained SHR expressed clear adaptive changes such as reduced resting heart rate and blood pressures, LPOA, homocysteine Therefore, treadmill exercise was sufficient to induce physiological adaptation in the SHR. Endurance training is known to induce physiological cardiac hypertrophy, while hypertension induces patho logical cardiac hypertrophy that increases cardiomyocyte apoptosis. The pathological adaptation to pressure overload has also been associated with a further increase in the expression of several marker genes including cardiomyocyte ET-1 in the SHR, but not in the exercise-trained SHR. Additionally, there is an increase in the endothelial nitricoxide synthases (eNOS) protein expression of soleus, gastrocnemius, and extensor digitorum longus muscle in the exercise-trained SHR but not in the SHR in the present study. Thus, compared to pathological adaptation to pressure overload, physiological adaptation to exercise training is associated with distinct alterations in cardiac and molecular phenotypes. based on these results, exercise training improves hypertension by cardiovascular regulating genes and hemodynamic parameters.

Characteristics of Central Noradrenergic Nervous System Response in SHR to Stimulation of Central ${\alpha}_2-Adrenoceptor$ (중추 ${\alpha}_2$-수용체 자극에 대한 선천성 고혈압쥐의 중추 노르아드레날린성 신경계 반응의 특성)

  • Chung, Hye-Joo;Oh, Uh-Taek;Ko, Kwang-Ho
    • YAKHAK HOEJI
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    • v.33 no.6
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    • pp.333-338
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    • 1989
  • It has been postulated that abnormal characteristics of central noradrenergic nervous system has been implicated in the development and maintenance of hypertension in several modes of experimental hypertension including spontaneously hypertensive rats (SHR). In the present study, we attempt to determine if abnormal characteristics of central noradrenergic nervous system in SHR is caused by genetic factors or hypertensive phenomena by evaluating the changes of central adrenoceptors after long-term treatment of clonidine. Animals were divided into three groups; (1) 14 week-old SHR; (2) age-matched normotensive Wistar rats (NW); (3) DOCA-Salt induced hypertensive rats (DS). Clonidine (100 ug/kg) or vehicle was injected intraperitonealy twice a day for 15 days. Changes of ${\alpha}_1-$ and ${\alpha}_2-receptor$ desities following clonidine treatment were determiend in frontal corte, medulla oblongata and hypothalamus using 3H-WB4101 and 3H-clonidine, respectively. Densities of ${\alpha}_1$ and ${\alpha}_2-receptors$ following clonidine treatment were not changed in frontal cortex and medulla oblongate of SHR as well as DS, but increased in frontal cortex of NW and decreased in medulla oblongata of NW. On the other hand, densities of ${\alpha}_1-receptors$ were increased and densities of ${\alpha}_2-receptors$ were not changed in hypothalamus of SHR but densities of ${\alpha}_1-$ and ${\alpha}_2-receptors$ were decreased in hypothalamus of DS as well as NW. These results suggest that such differences in frontal cortex and medulla oblongata of SHR may be results of hypertensive phenomena whereas those in hypothalamus may be relevant to genetic factors of SHR.

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Studies on the Antihypertensive Effect of Clonidine Administered Concurrently with Labetalol or Metoprolol in SHR (SHR에 Clonidine을 Labetalol 또는 Metoprolol과 병용투여후의 혈압강하에 관한 연구)

  • 허인회;김동섭;이종흔
    • YAKHAK HOEJI
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    • v.26 no.2
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    • pp.105-110
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    • 1982
  • The antihypertensive effect of clonidine administered concurrently with labetalol or metoprolol were studied with spontaneously hypertensive rats (SHR). The changes of heart rate were also observed in the same rats. Every drug was orally administered single dose after prechecking the systolic blood pressure and heart rate of SHR. The blood pressure of SHR in concurrently administered group was more significantly decreased than in alone administered group. The effective and stable decrease of blood pressure was maintained at the group of clonidine with labetalol (0.05+50mg/kg) for 9 hours. The group of clonidine with metoprolol (0.05+100mg/kg) manifested more marked decrease of blood pressure than the group of metoprolol (100mg/kg) alone for 9 hours. The diminishing effect of heart rate was enhanced in group of administering clonidine with labetalol, decreasing the dose of labetalol from 50mg/kg via 25mg/kg to 12.5mg/kg. On the other hand, in the group that clonidine was administered concurrently with metoprolol, the diminishing effect of heart rate was decreased with decreasing doses of metoprolol from 100mg/kg via 50mg/kg to 25mg/kg.

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The Preventative Effect of Gamibangpungtongsungsan (KBTS) on Hypertension (가미방풍통성산의 항고혈압 작용)

  • Ha, Yeo-Tae;Kim, Dong-Hee
    • Journal of Haehwa Medicine
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    • v.14 no.2
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    • pp.55-70
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    • 2005
  • In oriental medicine, Gamibangpungtongsungsan (KBTS) has been used as a therapeutic agent for the treatments of acute stage of cerebrovascular diseases and hypertension. In the present study, underlying mechanism on KBTS effects was investigated using spontaneously hypertensive rats (SHR) by determining related parameters such as blood pressure, heart-beat rates, and hormones and plasma constituents. The major finding are summarized as follows. 1. KBTS treatment at concentrations lower than $125\;{\mu}g/m{\ell}$ did not show any cytotoxicity on cultured human fibroblast cells. 2. KBTS treatment in SHR significantly decreased blood pressure and heart-beat rate compared with untreated control. 3. KBTS treatment in SHR decreased aldosterone levels in the blood compared with untreated control, but the difference was not statistically significant. 4. KBTS treatment in SHR significantly decreased dopamine, norepinephrine and epinephrine levels in the blood compared with untreated control. 5. KBTS treatment in SHR decreased plasma ion concentrations such as Na+, K+, Ca2+, Cl- compared with untreated control; decreases in Na+ and Cl- were statistically significant. 6. KBTS treatment in SHR significantly decreased TNF-$\alpha$, IL-6, and IL-10 levels in the blood compared with untreated control. Thus, the present data show evidence on anti-hypertension activity of KBTS in an experimental animal system, which can provide further insights into the development of anti-hypertension therapeutic agents.

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Kami-bang-pung-tong-sung-san is Involved in Regulating Physiological Parameters Associated with Hypertension in Spontaneously Hypertensive Rat

  • Na Young Cheul;Nam Gung Uk;Lee Yang Koo;Kim Dong Hee
    • 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.

Electroacupuncture Delays Development of Hypertension through Increase of NO Level in Spontaneously Hypertensive Rats

  • Hwang, Hye-Suk;Kim, Yu-Sung;Lee, Ji-Eun;Han, Kyung-Ju;Choi, Sun-Mi;Koo, Sung-Tae
    • Korean Journal of Oriental Medicine
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    • v.13 no.2
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    • pp.149-155
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    • 2007
  • Objective : Using a spontaneously hypertensive rat (SHR) model of essential hypertension, this study investigated whether electroacupuncture (EA) could reduce early stage hypertension by examining whether EA increased nitric oxide (NO) levels in plasma, which compensates for elevated blood pressure (BP). Methods : EA was applied to the acupoint, Baekhoe (GV20), and to a non acupoint in the tail at 10 Hz and an intensity of 1 mA for 10 minutes on the first and fourth day of the week for three weeks under isoflurane anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY) rats, blood pressure was determined the day after EA treatment by the tail cuff method using an automatic BP monitoring system. We also measured NO concentration of blood serum in SHR and WKY. Results : Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower after 3 weeks of GV20 treatment than in non EA treated or non acupoint treated SHR rats. The NO level of plasma was significantly lower in hypertensive SHR than in normotensive WKY. EA prevented the augmentation of blood pressure, and also increased NO concentrations from $7.91{\pm}0.42$ ${\mu}M$ to $11.50{\pm}0.93$ ${\mu}M$ in SHR serum. Conclusions : We suggest that acupuncture may be an early intervention to delay the development of hypertension and enhance NO/NOS activity.

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Antihypertensive Effect of Wild Mountain Ginseng Cultured Root Extract in Spontaneously Hypertensive Rats (Spontaneously Hypertensive Rats에 있어서 산삼배양근 추출물의 항고혈압 효과)

  • Yang, Deok-Chun;In, Jun-Gyo;Lee, Bum-Soo;Han, Seung-Ho;Kim, Eun-Jeong;Kim, Kil-Soo
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.6
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    • pp.1482-1486
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    • 2008
  • The antihypertensive effects of the Wild Mountain Ginseng Cultured Root Extract (WMGCE) were investigated in spontaneously hypertensive rats (SHR). Daily oral administration of the WMGCE (100 and 200 mg/kg) exhibited a significant decrease in blood pressure in SHR rats during for 8 weeks. The systolic blood pressure was dose- and time-dependently decreased significantly from the second weeks (p < 0.05) to the end of WMGCE treatment in SHR. The WMGCE decreased the plasma levels of sodium, potassium, chlorides, urea and osmolarity in SHR rats but no statistically significant change was observed. Furthermore, no significant changes were noted on heart weight, heart rate and diameter of aorta after WMGCE treatment in SHR. Our results suggest that daily oral administration of WMGCE at the dose of 100 and 200 mg/kg for 8 weeks exhibited antihypertensive activities.

Effects of Atrial Natriuretic Peptide on Renal and Endocrine Functions in Spontaneously Hypertensive Rats (Spontaneously Hypertensive Rat에 있어서 Atrial Natriuretic Peptide의 신장기능과 몇가지 호르몬 분비에 미치는 영향)

  • Kim, San-Ho;Kim, Suhn-Hee;Seul, Kyung-Hwan;Cho, Kyung-Woo
    • 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.

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Increase in $Na^+-Ca^{2+}$ Exchange Activity in Sarcolemma Isolated from Mesenteric Arteries of Spontaneously Hypertensive Rats

  • Lee, Shin-Woong;Lee, Jeung-Soo;Park, Young-Joo;Park, In-Sook
    • Archives of Pharmacal Research
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    • v.12 no.2
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    • pp.128-134
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    • 1989
  • $Na^+-Ca^{2+}$ exchange process in sarcolemmal vesicles isolated from mesenteric arteries of Wistar-Kyoto normotensive(WKY) and spontaneously hypertensive rats(SHR) was investigated. The sarcolemmal fractions isolated after homogenization and sucrose density gradient centrifugation were enriched with 5'-nucleotidase and ouabain sensitive, $K^+-dependent$ phosphatase activities. When the vesicles were loaded with $Na^+$, a time dependent $Ca^{2+}$ uptake was observed. However, very little $Ca^{2+}$ uptake was observed when the vesicles were loaded with $K^+$, or $Ca^{2+}$ uptake of the $Na^+-loaded$ vesicles was carried out in high sodium medium so that there was no sodium gradient. When the vesicles loaded with $Ca^{2+}$ by $Na^+-Ca^{2+}$ exchange were diluted into potassium medium containing EGTA, $Ca^{2+}$ was rapidly released from the vesicles. $Na^+-dependent\;Ca^{2+}$ uptake was increased in SHR compared to WKY, but passive efflux of preaccumulated $Ca^{2+}$ from the vesicles was decreased in SHR. The data indicate that the membrane vesicles of rat mesenteric arteries exhibit $Na^+-Ca^{2+}$ exchange activity. It is also suggested that changes of this process in vascular smooth muscle cell membrane of SHR may be involved in higher intracellular $Ca^{2+}$ concentration and higher basal tone in SHR.

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Dietary Sodium Effects on Responses of Atrial Natriuretic Peptide, Aldosterone and Renin Release to Acute Volume Expansion in SHR (장기간 고염 섭취한 SHR 고혈압 쥐에서, 급성 혈장량 증가에 대한 Atrial Natriuretic Peptide, Aldosterone 및 Renin 분비 반응의 비교)

  • Kim, Ae-Ra;Lee, Won-Jung;Choo, Young-Eun;Kim, Suhn-Hee;Cho, Kyung-Woo
    • The Korean Journal of Physiology
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    • v.23 no.2
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    • pp.253-261
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    • 1989
  • Responses of atrial natriuretic peptide (ANP), aldosterone and renin release to acute volume expansion were compared in normotensive Wistar and spontaneously hypertensive rat (SHR) fed low or high-sodium diet (2 or 25 mmol Na/100 g diet). Experimental diets were fed for 6 weeks from 7-week-old and the growth rate was similar in all groups. In the morning of the experiment, catheters were inserted under ether anesthesia in femoral artery for pressure recording and blood collection, femoral vein for saline infusion, and bladder for urine collection. Then, the rats were placed in restraining cages. When the rats were recovered from anesthesia and the arterial pressure became stabilized, control urine and blood samples were collected. Then, 0.9% saline was infused for 30 min for volume expansion (3% BW). Arterial pressure was significantly higher in the high-sodium SHR but there was no difference between the two groups of Wistar rats. Control plasma levels of Na, K, ANP, renin activity, and hematocrit were not different among the 4 groups. However, plasma aldosterone level was significantly higher in the low-sodium groups. Wistar low-sodium rats showed approximately two times higher plasma aldosterone level than the SHR counterpart. Volume expansion produced a marked increase in plasma ANP level, especially in the high-sodium groups. The low-sodium groups of both strains showed approximately two-fold increase in plasma ANP level. Following a volume expansion plasma aldosterone level and renin activity decreased in all groups. There was a significant logarithmic positive correlation between plasma renin activity and aldosterone concentration. The low-sodium rats produced a greater increase in aldosterone release by small increase in plasma renin than did the high-sodium rats. The low- and high-sodium rats produced a similar degree of diuresis and natriuresis after volume expansion. However, SHR produced a greater natriuresis than did the Wistar rats. The above results indicate that regulatory mechanisms of ANP, aldosterone and renin release are different between the normotensive and hypertensive rats, and between the low- and high-sodium groups.

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