• 대한약리학회지
• /
• 제31권1호
• /
• pp.17-26
• /
• 1995

8주, 18주, 그리고 32주된 Spontaneously Hypertensive Rats (SHR)과 Wistar-Kyoto Rats(WKY)과의 blood pressure(혈압)를 측정하여본 결과 SHR 그룹이 WKY에 비해 19에서 70 mmHg 차이로 SHR 그룹이 WKY group에 비하여 혈압이 높았다. 18주된 SHR과 WKY에서 제 3 뇌실내 (intraventricular)로 투여된 morphine과 ${\beta}-endorphin$의 진통작용을 검색하여 보았다. WKY group에 비하여 SHR group에서 뇌실내로 투여된 ${\beta}-endorphin$은 진통작용에 있어서 상승작용 (potentiation)을 보임을 발견하였고 뇌실내로 투여된 morphine은 SHR group에서 약간만 상승작용을 보였다. SHR과 WKY group간에 opioid의 진통작용에 있어서 중요한 역할을 하는 Midbrain과 Medulla (pons), 그리고 spinal cord (척수)의 lumbar부위의 $[Met^5]-enkephalin$과 proenkep-halin A mRNA level을 측정하여 보았다. SHR과 WKY group간의 $[Met^5]-enkephalin$과 proenkephalin mRNA의 양은 별로 차이를 보이지 않았다. 이러한 결과로 미루어 볼때 SHR group에서 뇌실내로 투여된 ${\beta}-endorphin$은 그의 진통효과에 있어서 보인 상승작용은 척수상부에 위치하고 있는 opioid deptide의 양이 변해서가 아니라 다른 기전에 의하여 조절되어지고 있음을 시사한다.

• 한국한의학연구원논문집
• /
• 제13권2호통권20호
• /
• pp.149-155
• /
• 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.

• Environmental Analysis Health and Toxicology
• /
• 제7권1_2호
• /
• pp.59-65
• /
• 1992

The role of central dopaminergic neural activity for the maintenance of hypertension was tested. Two groups of animals were prepared; 1) Spontaneously hypertensive rats (SHR) at 14 weeks of age which reveal hypertension and 2) age-matched normotensive Wistar Kyoto rats (WKY). Blood pressures and dopamine turnover rate were measured from animals in each group. Dopamine turnover rate was determined in four brain regions such as telence-phalon, hypothalamus/thalamus, midbrain and pons/medulla, from concentration of dopamine at time zero, 1 and 2 hours after alpha-methyl-para-tyrosine (AMPT) was injected into animals. In SHR dopamine turnover rate was greater than normotensive rats in only midbrain. The result from the present study implicates that dopaminergic neural activity in midbrain may be positively coupled to the manifestation of hypertension in SHR.

• Biomolecules & Therapeutics
• /
• 제1권2호
• /
• pp.220-225
• /
• 1993

Effect of BR-900317 on the angiotensin I-induced pressor response in pithed rats and the effects of its single oral administration on plasma angiotensin converting enzyme (ACE) activities in normotensive rats and on the cardiovascular system in hypertensive model rats (SHR, RHR), were compared with those of captopril. BR-900317 attenuated the angiotensin I-induced pressor effects in pithed rats. In a single oral dose administration study, BR-900317 inhibited the plasma ACE activities in a dose-dependent fashion. Duration of the action of BR-900317 was similar to that of captopril. BR-900317 produced antihypertensive effect in spontaneously hypertensive rats and dose-dependent antihypertensive effect in 2-kidney Goldblatt hypertensive rats without affecting heart rate. These results suggest that the main mechanism of the antihypertensive effect of BR-900317 is the suppression of angiotensin II production due to the inhibition of the ACE.

• Journal of Nutrition and Health
• /
• 제22권2호
• /
• pp.91-101
• /
• 1989

This study was performed to investigate the effects of different dietary magnesium levels on systolic blood pressure and mineral distribution in normotensive and spontaneously hypertensive rats. In experiment 1, Normotensive rats(NTR ; Sprague Dawley, Female) were given diets containing regular magnesium (0.05% Mg ; rMg), marginal magnesium (0.01% Mg ; mMg) or marginal magnesium with stress(0.01% Mg + stress ; mMg + Str). In experiment 2, spontaneously hypertensive rats (SHR ; Kyoto Wistar, Femal) were fed diets containing regular magnesium(0.05% Mg ; rMg) and high magnesium (0.2% Mg ; hMG). The following were found ; 1) NTR treated with marginal magnesium with stress showed significant increase in systolic blood pressure (SBP). Marginal magnesium diet without stress resulted in nonsignificant increase in SBP. Significant in crease of blood pressure showed in NTR treated with marginal magnesium and stress was associated with decreased magnesium and increased calcium content in femur, reticulocyte and plasma. 2) In experiment 2, magnesium supplementation to SHR showed significant attenuation of their systolic blood pressure with increasing age. The attenuation of SBP showed in SHR was associated with increased magnesium, lowered calcium content in cardiac muscle and reticulocyte and decreased plasma sodium and aldosterone level.

• 생약학회지
• /
• 제30권2호
• /
• pp.226-230
• /
• 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.

• 대한본초학회지
• /
• 제26권1호
• /
• pp.75-80
• /
• 2011

Objectives : The aim of the present study is to investigate the hypotensive effect of Samhwangsasim-tang (SHSST), Samigangap-tang (SMGAT) and Bangtan-tang (BTT) in stroke-prone spontaneously hypertensive rats (SHR-SP). Methods : SHR-SP rats were treated with SHSST, SMGAT and BTT at dose of 200 mg/kg/day orally for 5 weeks, respectively. Results : Treatment SHR-SP rats with SMGAT significantly lowered blood pressure but not in the SHSST or BTT treat groups. On the other hand, SHSST, SMGAT and BTT ameliorated endothelium-dependent and independent vascular relaxation in the phenylephrine-precontracted aorta and carotid artery, respectively. Conclusions : These results indicated that SMGAT has an antihypertensive effect and SHSST, SMGAT and BTT improve vascular function in stroke-prone hypertensive rat model, respectively.

• 대한수의학회지
• /
• 제45권4호
• /
• pp.537-544
• /
• 2005

We have examined distribution and expression of caveolin-3 (cav-3), one of three caveolin isoforms from 16-wks-old spontaneously hypertensive rats (SHR) compared with age-matched control wistar-kyoto (WKY) rats. The expression of cav-3 was increased, whereas expression of PKB/Akt and calcineurin (Cn) was not changed in cardiac tissues of SHR compared to WKY rats. Interestingly, expression of cav-3, PKB/Akt and Cn were decreased in plasma membrane fraction in SHR compared to WKY rats. In H9c2 cardiomyoblast cells treated with phenylephrine ($50{\mu}M$, 48hr) or isoproterenol ($10{\mu}M$, 48hr), the expression of cav-3 was markedly enhanced compared to nontreated cells. Upon immunofluorescence analysis, cav-3 was localized in plasma membrane of control H9c2 cells. However phenylephrine or isoproterenol treatment caused translocation of cav-3 to perinuclear region. These results suggest that cav-3 plays as positive regulators in the development of hypertrophy in cardiac tissues of SHR rats.

• 약학회지
• /
• 제29권6호
• /
• pp.367-374
• /
• 1985

The age-related changes of monoamine contents and monoamine oxidase (MAO) activities in the whole brain and blood pressures were measured and compared every week during the ages of 5 weeks to 12 weeks in two types of animals; (1) spontaneously hypertensive rats (SHR) and (2) normotensive Sprague-Dawley rats (NR). Blood pressures in SHR began to rise at the ages of 7 or 8 weeks and were significantly higher thereafter than in NR. Abnormally low MAO activities in the brain of SHR were detected from the ages of 8 weeks. Comparisons were also made between brain monoamine-norepinephrine, dopamine and 5-hydroxytrytamine contents of SHR and those of NR at the same ages throughout the test period. In SHR, none of those monoamine values was consistently higher or lower than in NR during the test period. Protein contents of the brain between SHR and NR were not significantly different at any ages. These observations suggest that the abnormally low MAO activities in SHR brain may be one of the underlying neurological factors for the susceptibilities to hypertension and the deficit of MAO activities may be due to the changes in properties rather than in amount of this enzyme.

• Journal of Yeungnam Medical Science
• /
• 제34권1호
• /
• pp.43-54
• /
• 2017

Background: Extracellular sulfatases (Sulfs), sulfatase 1 (Sulf1) and sulfatase 2 (Sulf2), play a pivotal role in cell signaling by remodeling the 6-O-sulfation of heparan sulfate proteoglycans on the cell surface. The present study examined the effects of Sulfs on angiotensin II (Ang II)-induced hypertensive mediator expression and vascular smooth muscle cells (VSMCs) proliferation in spontaneously hypertensive rats (SHR). Methods: Ang II receptors, 12-lipoxygenase (12-LO), and endothelin-1 (ET-1) messenger RNA (mRNA) expressions in SHR VSMCs were analyzed by real-time polymerase chain reaction and Western blotting. VSMCs proliferation was determined by [$^3H$]-thymidine incorporation. Results: Basal Sulfs mRNAs expression and enzyme activity were elevated in SHR VSMCs. However, Sulfs had no effect on the basal or Ang II-induced 12-LO and ET-1 mRNA expression in SHR VSMCs. The inhibition of Ang II-induced 12-LO and ET-1 expression by blockade of the Ang II type 2 receptor ($AT_2\;R$) pathway was not observed in Sulf1 siRNA-transfected SHR VSMCs. However, Sulf2 did not affect the action of $AT_2\;R$ inhibitor on Ang II-induced 12-LO and ET-1 expression in SHR VSMCs. The down-regulation of Sulf1 induced a reduction of $AT_2\;R$ mRNA expression in SHR VSMCs. In addition, the inhibition of Ang II-induced VSMCs proliferation by blockade of the $AT_2\;R$ pathway was mediated by Sulf1 in SHR VSMCs. Conclusion: These findings suggest that extracellular sulfatase Sulf1 plays a modulatory role in the $AT_2\;R$ pathway that leads to an Ang II-induced hypertensive effects in SHR VSMCs.