• Title, Summary, Keyword: SHR

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Regular Endurance Exercise Decreases Blood Pressure via Enhancement of Angiogenesis and VEGF Expression in Spontaneously Hypertensive Rats (규칙적인 지구성운동이 고혈압쥐 골격근의 혈관생성과 VEGF 발현의 증가를 통한 혈압감소에 미치는 효과)

  • Li, Wei;Park, Hee-Geun;Lee, Young-Ran;Jang, Hak-Young;Choo, Sung-Ho;Lee, Young-Hwa;Gan, Li;Jun, Jong-Kui;Lee, Wang-Lok;Lee, Sang-Ki
    • Journal of Life Science
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    • v.22 no.5
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    • pp.665-670
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    • 2012
  • This study investigated the effect of endurance exercises on blood pressure, angiogenesis, and the vascular endothelial growth factor (VEGF) expression in the skeletal muscle of spontaneously hypertensive rats (SHR). Five week old SHRs and Wistar-Kyoto rats (WKY) were randomly divided into 3 groups: Wistar-Kyoto rats (WKY, n=9), SHR control (SHR-C, n=9), and SHR endurance exercise training (SHR-E, n=9). Endurance exercise training was performed on a treadmill (12-20 m/min, 0% grade, 60 min/day, 5 days/week, 16 weeks). Systolic blood pressure was monitored with the tail-cuff method. The expression of VEGF protein and capillary density were identified using western blotting and H&E staining in the soleus muscle, respectively. Systolic blood pressure was reduced by endurance exercise in SHR ($p$ <0.05). The capillary density of skeletal muscles in SHR-C was lower than in WKY ($p$ <0.05), but it was recovered by endurance exercise training (SHR-E) compared to SHR-C ($p$ <0.05), and VEGF protein was also increased by endurance exercise training compared to SHR-C ($p$ <0.05). These data suggest that the enhancement of capillary density via an increase of VEGF expression in skeletal muscles by endurance exercise training could be an important factor to inhibit blood pressure elevation in SHR.

Effect of Ovarian Steroid Hormones on Catecholaminergic Nervous System in the Hypothalamus of SHR (선천성 고혈압 쥐에서 시상하부 카테콜아민성 신경계에 미치는 난소 스테로이드 호르몬의 영향)

  • 김운자;고광호
    • YAKHAK HOEJI
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    • v.35 no.5
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    • pp.394-400
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    • 1991
  • A question whether abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steoid hormones in spontaneously hypertensive rats (SHR) exist was investigated. Four groups of experimental animals were prepared for SHR and normotensive Wistar rats (NW) respectively: 1) intact, 2) ovariectomized (OVX+V), 3) ovariectomized and estrogen treated (OVX+E), 4) ovariectomized and estrogen plus progesterone treated (OVX+E+P) groups. Hypothalami from experimental animals were dissected out and used for determination of .alpha.-adrenergic receptor binding characteristics and catecholamine contents. Norepinephrine(NE) content and B$_{max}$ of $\alpha_1$-adrenergic receptors in hypothalami were greater in intact SHR than in intact NW, but dopamine(DA) content was lower in SHR than in NW. Neither contents of NE and DA nor binding characteristics of $\alpha_1$-adrenergic receptors were different in OVX+V and OVX+E group from intact group of both SHR and NW. Kd and B$_{max}$ of $\alpha_1$-adrenergic receptors in OVX+E+P was lower than that in intact SHR but not in NW. DA content was lower in OVX+E+P than in intact group of SHR and NW. The result of the present study indicates that there is an abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steroid hormones in SHR which may be one of genetically-determined factors probably not responsible for the development of hypertension.

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Cholinergic Activity Related to Cardiovascular Regulation in Rostral Ventrolateral Medulla of Spontaneously Hypertensive Rats

  • Lee, Seok-Yong;Lee, Sang-Bok
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.1
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    • pp.29-34
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    • 1999
  • The hyperactivity of cholinergic system in the RVLM of spontaneously hypertensive rats (SHR) may contribute to the sustained elevation of blood pressure. However, the hyperactivity mechanisms of cholinergic system are controversial. Thus, to clarify the mechanisms of cholinergic hyperactivity in RVLM of the SHR, we studied the activities of enzymes that participate in the biosynthesis and degradation of acetylcholine (ACh) and the density of muscarinic receptors in RVLM of the 14- to 18-week-old SHR and age-marched Wistar Kyoto rats (WKY). Choline acetyltransferase activity was far greater in RVLM of SHR than that of WKY. $[^3H]ACh$ release from RVLM was also greater in SHR than in WKY. Acetylcholinesterase activity and $[^3H]NMS$ binding of RVLM slice of SHR were not significantly different from that of WKY. These results suggest that the enhanced cholinergic mechanisms in the RVLM of SHR is due to the enhanced presynaptic cholinergic tone rather than the altered postsynaptic mechanisms.

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Study of the Antinociception Induced by Opioids and the Proenkephalin Gene Expression in Spontaneously Hypertensive Rats (선천성 고혈압쥐에서의 Opioid에 의한 진통작용과 Proenkephalin유전자 발현에 대한 연구)

  • Suh Hong-Won;Lee Tae-Hee;Song Dong-Keun;Choi Seong-Ran;Jung Jun-Sub;Kim Yung-Hi
    • The Korean Journal of Pharmacology
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    • v.31 no.1
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    • pp.17-26
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    • 1995
  • The present studies were carried out to determine if antinociceptive action of morphine and ${\beta}-endorphin$ administered intraventricularly was changed in. pentobarbital anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Antinociception was assessed by the tail-flick test. The $ED_{50}$ values of antinociception for morphine administered intraventricularly were 1.9 and 1.2 nmol for WKY and SHR rats, respectively. The $ED_{50}$ values of antinociception for ${\beta}-endorphin$ administered intraventricularly were 0.40 and 0.12 nmol for WKY and SHR rats, respectively. The $[Met^5]-enkephalin$ (ME) and proenkephalin mRNA levels in midbrain, pons and medulla, or lumbar section of the spinal cord in WKY and SHR rats were measured by the radioimmunoassay and Northern blot assay, respectively. There were no differences of ME and proenkephalin mRNA levels in these tissues between WKY and SHR rats. The results suggest that ${\beta}-endorphin$ but not morphine administered intraventricularly produces a greater antinociception in SHR rats. This increased antinociceptive effect of ${\beta}-endorphin$ in SHR rats may be not, at least, due to the alterations of ME And proenkephalin mRNA levels in the midbrain, pons and medulla, or spinal cord.

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Heme Oxygenase-l Induced by Aprotinin Inhibits Vascular Smooth Muscle Cell Proliferation Through Cell Cycle Arrest in Hypertensive Rats

  • Choi, Hyoung-Chul;Lee, Kwang-Youn;Lee, Dong-Hyup;Kang, Young-Jin
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.4
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    • pp.309-313
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    • 2009
  • Spontaneous hypertensive rats (SHR) are an established model of genetic hypertension. Vascular smooth muscle cells (VSMC) from SHR proliferate faster than those of control rats (Wistar-Kyoto rats; WKY). We tested the hypothesis that induction of heme oxygenase (HO)-1 induced by aprotinin inhibits VSMC proliferation through cell cycle arrest in hypertensive rats. Aprotinin treatment inhibited VSMC proliferation in SHR more than in normotensive rats. These inhibitory effects were associated with cell cycle arrest in the G1 phase. Tin protoporphyrin IX (SnPPIX) reversed the anti-proliferative effect of aprotinin in VSMC from SHR. The level of cyclin D was higher in VSMC of SHR than those of WKY. Aprotinin treatment downregulated the cell cycle regulator, cyclin D, but upregulated the cyclin-dependent kinase inhibitor, p21, in VSMC of SHR. Aprotinin induced HO-1 in VSMC of SHR, but not in those of control rats. Furthermore, aprotinin-induced HO-1 inhibited VSMC proliferation of SHR. Consistently, VSMC proliferation in SHR was significantly inhibited by transfection with the HO-1 gene. These results indicate that induction of HO-1 by aprotinin inhibits VSMC proliferation through cell cycle arrest in hypertensive rats.

Anti-hypertensive Effects of Pini Folium and Leonuri Herba Extract on Spontaneously Hypertensive Rat (SHR) (SHR(Spontaneously Hypertensive Rat)를 이용한 송엽, 익모초 추출물의 항고협알 작용)

  • 박건구;류재원;최은경;노환성
    • 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.

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Central noradrenergic mechanism in the regulation of blood pressure in SHR

  • 김연태
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.115-124
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    • 1995
  • The purpose of the present study was to address whether the in vivo noradrenergic neural activities in the locus coeruleus are involved in the regulation of blood pressure. Two groups of the animals were prepared, 1) SHR and 2) age-matched normotensive control, WKY. At the age of 6 and 16 weeks, blood pressure and the releases of NE from the locus coeruleus in SHR and KWY were measured by in vivo microdialysis at three different conditions: 1) normal, 2) elevated state of blood pressure by systemic injected phenylephrine and 3) increased state of neural activity by perfused phenylephrine into the locus coeruleus. The basal release of NE of SHR were significantly higher than that of WKY, Phenylephrine treatment caused elevation of blood pressure in both SHR and WKY in dose-dependent manner. Following phenylephrine injection, the releases of NE from the locus coeruleus of SHR were significantly decreased, whereas the significant change of NE in WKY was observed in the highest dose of phenylephrine. Phenylephrine perfusion into the locus coeruleus through microdialysis probe caused pressor responses and the pressor response in SHR was greater compared with that in WKY. The results from the present study suggests that the noradrenergic nervous system in the locus coeruleus may contribute as one of the development and maintenance factors for hypertension in SHR.

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Design and Performance Analysis of BLSR/4 WDM/SHR in All-Optical Transport Network (완전 광전달망에서 BLSR/4 WMD/SHR의 설계 및 성능 분석)

  • 강안구;최한규;김지홍;김광현;김호건;조규섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.10B
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    • pp.1832-1840
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    • 1999
  • This paper proposed a network to implement all optical bidirectional BLSR/4 WDM/SHR allowing restoration in the event of a failure. The proposed network can provide a high degree of transparency using all-optical components with no electric implementation and effective failure restoration due to BLSR/4 WDM/SHR architecture. This paper also presented a genetic simulation model for the survivability analysis of the proposed BLSR/4 WDM/SHR under failure scenarios, the restoration performance of the proposed network is analyzed in terms of performance parameters such as propagation time, processing time, optical switch time.

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Comparisons of Renoprotective Activities between White Ginseng Radix and Rootlet in Spontaneously Hypertensive Rats with Diabetes

  • Chung, Sung-Hyun;Ko, Sung-Kwon;Park, Se-Ho
    • The Korean Journal of Physiology and Pharmacology
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    • v.6 no.1
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    • pp.57-61
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    • 2002
  • The renoprotective activities of white ginseng radix and rootlet were compared in spontaneously hypertensive rat (SHR) with diabetes. During oral administration of white ginseng radix (Ginseng Radix Alba, GRA) and white ginseng rootlet (Ginseng Radix Palva, GRP) for four weeks, arterial blood pressure and blood glucose levels were determined at every 10 days. In both GRA- and GRP-treatment groups, arterial blood pressures started to go down after 10 days of administration and maintained throughout the study period. After four weeks administrations of GRA and GRP, diastolic blood pressures were significantly decreased with 17% and 9%, respectively. GRA treatment also decreased blood glucose levels after 10 days of administration when compared with diabetic SHR group. At the end of the experiment, serum creatinine (Scr) and blood urea nitrogen (BUN) were not significantly different between the groups, except 62% higher value of BUN in diabetic SHR group when compared with SHR group. In the diabetic SHR group, the excretion of urinary albumin was increased significantly when compared with SHR. The level of urinary albumin in GRA treated group was markedly reduced when compared with diabetic SHR group $(67.8{\pm}4.7\;vs.\;131.3{\pm}13.5\;mg/24\;h).$ To examine the effects of ginseng radices on an overt diabetic nephropathy, index of kidney hypertrophy and transforming growth $factor-{\beta}1\;(TGF-{\beta}1)$ protein levels were evaluated. The glomerular and tubular cells stained positive for $TGF-{\beta}1$ seemed to be more abundant in diabetic SHR than in those with SHR, and GRA treated rats showed somewhat less $TGF-{\beta}1$ protein in glomerular and tubular cells when compared with diabetic SHR. Our results suggest that GRA might be a useful antihypertensive and antidiabetic agent with renoprotective effect.

Altered Cerebral Vasomotion with Decreased CGRP Level in Pial Arteries of Spontaneously Hypertensive Rats

  • Lee, Kwang-Ho;Choi, Jae-Moon;Hong, Ki-Whan
    • The Korean Journal of Physiology and Pharmacology
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    • v.2 no.5
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    • pp.573-580
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    • 1998
  • The study aims to identify the mechanism (s) underlying the altered vasodilatory responses of the pial artery of spontaneously hypertensive rats (SHR) under a hypothesis that calcitonin gene-related peptide (CGRP) exerts a modulator role in the autoregulation of cerebral blood flow (CBF). The animals were divided into four groups: 1) Sprague-Dawley rats (SDR), 2) Wistar rats (WR), 3) SHR with high blood pressure $(BP{\ge}150\;mmHg),$ and 4) SHR with normotensive BP $({\le}150\;mmHg).$ The lower limit of CBF autoregulation in SHR shifted to a higher BP $(82.8{\pm}9.3\'mmHg,\;P<0.05)$ than that in SDR $(58.9{\pm}5.7\;mmHg)$. In SHR, whether the BP levels were high or normotensive, the vasodilator responses to a stepwise hypotension were significantly attenuated unlike with SDR and WR. When artificial cerebrospinal fluid (CSF) containing capsaicin $(3{\times}10^{-7}\;M)$ was suffused over the cortical surface, a transient increase in pial arterial diameter was observed in the SHR with high or normotensive BP. In contrast, SDR and WR showed a large increase in diameter, and the increase was sustained for over 10 minutes. In line with these results, the basal releases of CGRP-like immunoreactivity (CGRP-LI) in the isolated pial arteries from SHR with high and normotensive BP were $12.5{\pm}1.4\;and\;9.8{\pm}2.8\;fmole/mm^2/60\;min\;(P<0.05)$, while those from SDR and WR were $25.5{\pm}3.1\;and\;24.6{\pm}3.1\;fmole/mm^2/60\;min,$ respectively. The isolated basilar arteries showed similar results to those of the pial arteries in SHR. Thus, it is summarized that, in the SHR, the reduced autoregulatory vasodilator responses to stepwise hypotension and capsaicin may be, in part, ascribed to the decreased release of CGRP from the perivascular sensory nerve fibers of the pial arteries, and that altered vasomotor activity in SHR may not be related with the hypertensive tone.

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