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Murase S, Sakitani N, Maekawa T, Yoshino D, Takano K, Konno A, Hirai H, Saito T, Tanaka S, Shinohara K, Kishi T, Yoshikawa Y, Sakai T, Ayaori M, Inanami H, Tomiyasu K, Takashima A, Ogata T, Tsuchimochi H, Sato S, Saito S, Yoshino K, Matsuura Y, Funamoto K, Ochi H, Shinohara M, Nagao M, Sawada Y. Interstitial-fluid shear stresses induced by vertically oscillating head motion lower blood pressure in hypertensive rats and humans. Nat Biomed Eng 2023; 7:1350-1373. [PMID: 37414976 PMCID: PMC10651490 DOI: 10.1038/s41551-023-01061-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 05/27/2023] [Indexed: 07/08/2023]
Abstract
The mechanisms by which physical exercise benefits brain functions are not fully understood. Here, we show that vertically oscillating head motions mimicking mechanical accelerations experienced during fast walking, light jogging or treadmill running at a moderate velocity reduce the blood pressure of rats and human adults with hypertension. In hypertensive rats, shear stresses of less than 1 Pa resulting from interstitial-fluid flow induced by such passive head motions reduced the expression of the angiotensin II type-1 receptor in astrocytes in the rostral ventrolateral medulla, and the resulting antihypertensive effects were abrogated by hydrogel introduction that inhibited interstitial-fluid movement in the medulla. Our findings suggest that oscillatory mechanical interventions could be used to elicit antihypertensive effects.
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Affiliation(s)
- Shuhei Murase
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naoyoshi Sakitani
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Cell Biology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Takahiro Maekawa
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Daisuke Yoshino
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Kouji Takano
- Department of Rehabilitation for Brain Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Ayumu Konno
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hirokazu Hirai
- Department of Neurophysiology & Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Taku Saito
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sakae Tanaka
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Keisuke Shinohara
- Department of Cardiovascular Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takuya Kishi
- Department of Cardiology, Graduate School of Medicine, International University of Health and Welfare, Okawa, Japan
| | - Yuki Yoshikawa
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Takamasa Sakai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | | | - Hirohiko Inanami
- Inanami Spine & Joint Hospital/Iwai Orthopaedic Medical Hospital, Iwai Medical Foundation, Tokyo, Japan
| | - Koji Tomiyasu
- Center of Sports Science and Health Promotion, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Atsushi Takashima
- Department of Assistive Technology, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Toru Ogata
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
- Department of Rehabilitation Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Shinya Sato
- Department of Advanced Medical Technologies, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Shigeyoshi Saito
- Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kohzoh Yoshino
- School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
| | - Yuiko Matsuura
- Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan
| | | | - Hiroki Ochi
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Masahiro Shinohara
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Motoshi Nagao
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
| | - Yasuhiro Sawada
- Department of Rehabilitation for Motor Functions, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan.
- Department of Orthopaedic Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
- Department of Cell Biology, National Cerebral and Cardiovascular Center, Suita, Japan.
- Division of Advanced Applied Physics, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Japan.
- Department of Clinical Research, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan.
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Szczepanska-Sadowska E, Czarzasta K, Cudnoch-Jedrzejewska A. Dysregulation of the Renin-Angiotensin System and the Vasopressinergic System Interactions in Cardiovascular Disorders. Curr Hypertens Rep 2018; 20:19. [PMID: 29556787 PMCID: PMC5859051 DOI: 10.1007/s11906-018-0823-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Purpose of Review In many instances, the renin-angiotensin system (RAS) and the vasopressinergic system (VPS) are jointly activated by the same stimuli and engaged in the regulation of the same processes. Recent Findings Angiotensin II (Ang II) and arginine vasopressin (AVP), which are the main active compounds of the RAS and the VPS, interact at several levels. Firstly, Ang II, acting on AT1 receptors (AT1R), plays a significant role in the release of AVP from vasopressinergic neurons and AVP, stimulating V1a receptors (V1aR), regulates the release of renin in the kidney. Secondly, Ang II and AVP, acting on AT1R and V1aR, respectively, exert vasoconstriction, increase cardiac contractility, stimulate the sympathoadrenal system, and elevate blood pressure. At the same time, they act antagonistically in the regulation of blood pressure by baroreflex. Thirdly, the cooperative action of Ang II acting on AT1R and AVP stimulating both V1aR and V2 receptors in the kidney is necessary for the appropriate regulation of renal blood flow and the efficient resorption of sodium and water. Furthermore, both peptides enhance the release of aldosterone and potentiate its action in the renal tubules. Summary In this review, we (1) point attention to the role of the cooperative action of Ang II and AVP for the regulation of blood pressure and the water-electrolyte balance under physiological conditions, (2) present the subcellular mechanisms underlying interactions of these two peptides, and (3) provide evidence that dysregulation of the cooperative action of Ang II and AVP significantly contributes to the development of disturbances in the regulation of blood pressure and the water-electrolyte balance in cardiovascular diseases.
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Affiliation(s)
- Ewa Szczepanska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland.
| | - Katarzyna Czarzasta
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland
| | - Agnieszka Cudnoch-Jedrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-097, Warsaw, Poland
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A Decrease of Brain MicroRNA-122 Level Is an Early Marker of Cerebrovascular Disease in the Stroke-Prone Spontaneously Hypertensive Rat. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:1206420. [PMID: 28751928 PMCID: PMC5494068 DOI: 10.1155/2017/1206420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/21/2017] [Indexed: 02/06/2023]
Abstract
Based on preliminary evidence that highlights microRNA-122 as a contributing factor to stroke pathogenesis, we aimed at assessing its expression level, along with the presence of early signs of cerebrovascular disease, in the brain of stroke-prone spontaneously hypertensive rat (SHRSP), a suitable model of human disease that accelerates stroke occurrence under a high sodium/low potassium (Japanese-style) diet (JD). After one month of JD, before stroke occurrence, brain microRNA-122 level was significantly decreased in SHRSP as compared to the stroke-resistant SHR (SHRSR). At this time, levels of markers of oxidative stress and inflammation, as well as of endothelial integrity and function, apoptosis and necrosis were differently modulated in the brains of JD-fed SHRSP as compared to SHRSR, pointing to a significant activation of all deleterious mechanisms underlying subsequent stroke development in SHRSP. We also showed that miR-122 improved survival of rat endothelial cerebral cells upon stress stimuli (excess NaCl, hydrogen peroxide). Our data suggest that a decrease of brain microRNA-122 level is deleterious and can be considered as an early marker of stroke in the SHRSP. Understanding the mechanisms by which microRNA-122 protects vascular cells from stress stimuli may provide a useful approach to improve preventive and treatment strategies against stroke.
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ZHANG LIANGMIN, HE DEHUA, LIN JINXIU. Prehypertensive treatment with losartan, however not amlodipine, leads to long-term effects on blood pressure and reduces the risk of stroke in spontaneously hypertensive stroke-prone rats. Mol Med Rep 2015; 13:1304-10. [DOI: 10.3892/mmr.2015.4641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 09/10/2015] [Indexed: 11/05/2022] Open
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He DH, Zhang LM, Lin LM, Ning RB, Wang HJ, Xu CS, Lin JX. Long-term prehypertension treatment with losartan effectively prevents brain damage and stroke in stroke-prone spontaneously hypertensive rats. Int J Mol Med 2013; 33:301-9. [PMID: 24337406 PMCID: PMC3896471 DOI: 10.3892/ijmm.2013.1583] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 11/28/2013] [Indexed: 02/07/2023] Open
Abstract
Prehypertension has been associated with adverse cerebrovascular events and brain damage. The aims of this study were to investigate i) whether short- and long-term treatments with losartan or amlodipine for prehypertension were able to prevent blood pressure (BP)-linked brain damage, and ii) whether there is a difference in the effectiveness of treatment with losartan and amlodipine in protecting BP-linked brain damage. In the present study, prehypertensive treatment with losartan and amlodipine (6 and 16 weeks treatment with each drug) was performed on 4-week-old stroke-prone spontaneously hypertensive rats (SHRSP). The results showed that long-term (16 weeks) treatment with losartan is the most effective in lowering systolic blood pressure in the long term (up to 40 weeks follow-up). Additionally, compared with the amlodipine treatment groups, the short- and long-term losartan treatments protected SHRSP from stroke and improved their brains structurally and functionally more effectively, with the long-term treatment having more benefits. Mechanistically, the short- and long-term treatments with losartan reduced the activity of the local renin-angiotensin-aldosterone system (RAAS) in a time-dependent manner and more effectively than their respective counterpart amlodipine treatment group mainly by decreasing AT1R levels and increasing AT2R levels in the cerebral cortex. By contrast, the amlodipine treatment groups inhibited brain cell apoptosis more effectively as compared with the losartan treatment groups mainly through the suppression of local oxidative stress. Taken together, the results suggest that long-term losartan treatment for prehypertension effectively protects SHRSP from stroke-induced brain damage, and this protection is associated with reduced local RAAS activity than with brain cell apoptosis. Thus, the AT1R receptor blocker losartan is a good candidate drug that may be used in the clinic for long-term treatment on prehypertensive populations in order to prevent BP-linked brain damage.
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Affiliation(s)
- De-Hua He
- Department of Cardiology, The First Affiliated Hospital of Xiamen University, Fuzhou, Fujian, P.R. China
| | - Liang-Min Zhang
- Department of Cardiology, The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, P.R. China
| | - Li-Ming Lin
- Department of Cardiology, Affiliated Hospital of Putian College, Fuzhou, Fujian, P.R. China
| | - Ruo-Bing Ning
- Department of Cardiology, The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, P.R. China
| | - Hua-Jun Wang
- Fujian Institute of Hypertension, Fuzhou, Fujian, P.R. China
| | - Chang-Sheng Xu
- Fujian Institute of Hypertension, Fuzhou, Fujian, P.R. China
| | - Jin-Xiu Lin
- Department of Cardiology, The First Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, P.R. China
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Takemori K, Inoue T, Ito H. Effects of angiotensin II type 1 receptor blocker and adiponectin on adipocyte dysfunction in stroke-prone spontaneously hypertensive rats. Lipids Health Dis 2013; 12:108. [PMID: 23876211 PMCID: PMC3750705 DOI: 10.1186/1476-511x-12-108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/18/2013] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Hypoadiponectinemia in lipoatrophy may be related to worsening of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). One of the beneficial effects of candesartan (Angiotensin II Type 1 receptor blocker) for preventing hypertension may be increasing of adiponectin due to improvement of adipocyte dysfunction. In this study, we determined the effects of candesartan or adiponectin on pathophysiologic features and adipocyte dysfunction in SHRSP. METHODS Candesartan was administered to male SHRSP from 16 to 20 weeks of age (2 mg/kg/day). Adiponectin was cloned and intravenously administered to male SHRSP from 16 to 20 weeks of age. We examined biological parameters, as well as the expression and release of adipokines. RESULTS The SHRSP exhibited severe atrophy of visceral fat and progression of severe hypertension. The expression and release of leptin and adiponectin were impaired at 6 and 20 weeks of age. Candesartan suppressed the development of lipoatrophy and reduced the incidence of stroke at 20 weeks of age. Candesartan also enhanced the expression of adiponectin and leptin by inducing the overexpression of peroxisome proliferator activated receptor γ. Circulating level of leptin was significantly higher in candesartan group than in the control group, whereas adiponectin was similar in both groups. Intravenous administration of adiponectin resulted in enhancement of adiponectin expression in adipose tissue, but no remarkable effects were found in pathophysiology in SHRSP. CONCLUSIONS Our results indicate that candesartan protects against hypertension and adipocyte dysfunction in SHRSP. The induction of leptin expression appeared to be important factor in the inhibition of stroke lesions, whereas adiponectin was not a major regulator of blood pressure in SHRSP with genetic hypertension. Further studies are needed to elucidate the role of the renin-angiotensin system in adipose tissue dysfunction in relation to hypertensive end-organ damage.
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Affiliation(s)
- Kumiko Takemori
- Department of Food Science and Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
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Kishi T, Hirooka Y, Sunagawa K. Telmisartan protects against cognitive decline via up-regulation of brain-derived neurotrophic factor/tropomyosin-related kinase B in hippocampus of hypertensive rats. J Cardiol 2012; 60:489-94. [PMID: 22948091 DOI: 10.1016/j.jjcc.2012.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 05/24/2012] [Accepted: 06/20/2012] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND PURPOSE Cognitive decline may occur as a result of hypertension, and is dependent on the function of hippocampus. Brain-derived neurotrophic factor (BDNF) mediated by angiotensin II-induced oxidative stress protects against cell death in hippocampus. Angiotensin II receptor blocker (ARB), candesartan, activates BDNF in the hippocampus. Furthermore, peroxisome proliferator-activated receptor (PPAR)-gamma activation in the brain prevents brain damage. Telmisartan, a unique ARB with PPAR-gamma stimulating activity, protects against cognitive decline partly because of PPAR-gamma activation. The aim of the present study was to determine whether telmisartan protects against cognitive decline via up-regulation of BDNF and its receptor tropomyosin-related kinase B (TrkB) in the hippocampus of hypertensive rats, partly because of PPAR-gamma activation. METHODS AND RESULTS We divided stroke-prone spontaneously hypertensive rats (SHRSPs), as hypertensive and vascular dementia model rats, into five groups, telmisartan-treated (TLM), TLM+GW9662, a PPAR-gamma inhibitor, -treated (T+G), GW9662-treated (GW), TLM+ANA-12, a TrkB antagonist, -treated (T+A), and vehicle-treated SHRSPs (VEH). After the treatment for 28 days, systolic blood pressure did not change in all groups. However, BDNF expression in the hippocampus was significantly higher in TLM than in VEH to a greater extent than in T+G. Cognitive performance was significantly higher in TLM than in VEH to a greater extent than in T+G, and was not different between T+A, GW, and VEH. CONCLUSION Telmisartan protects against cognitive decline via up-regulation of BDNF/TrkB in the hippocampus of SHRSPs, partly because of PPAR-gamma activation independent of blood pressure-lowering effect.
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Affiliation(s)
- Takuya Kishi
- Department of Advanced Therapeutics for Cardiovascular Diseases, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
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Synergism of Telmisartan and Amlodipine on Blood Pressure Reduction and Cardiorenal Protection in Hypertensive Rats. J Cardiovasc Pharmacol 2011; 57:308-16. [DOI: 10.1097/fjc.0b013e3182073e41] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Song SW, Liu AJ, Bai C, Su BL, Ma XJ, Shen FM, Duan JL, Su DF. Blood pressure reduction combining baroreflex restoration for stroke prevention in hypertension in rats. Front Pharmacol 2010; 1:6. [PMID: 21713105 PMCID: PMC3112284 DOI: 10.3389/fphar.2010.00006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Accepted: 05/06/2010] [Indexed: 11/13/2022] Open
Abstract
Blood pressure reduction is an important and effective strategy in stroke prevention in hypertensives. Recently, we found that baroreflex restoration was also crucial in stroke prevention. The present work was designed to test the hypothesis that a combination of blood pressure reduction and baroreflex restoration may be a new strategy for stroke prevention. In Experiment 1, the effects of ketanserin (0.3, 1, 3, 10 mg/kg), amlodipine (0.3, 1, 2, 3 mg/kg) and their combination (1 + 0.3, 1 + 1, 1 + 2, 1 + 3 mg/kg) on blood pressure and baroreflex sensitivity (BRS) of stroke-prone spontaneously hypertensive rats (SHR-SP) were determined under conscious state. It was found that both amlodipine and ketanserin decreased blood pressure dose-dependently. Ketanserin enfanced BRS from a very small dose but amlodipine enfanced BRS only at largest dose used. At the dose of 1 + 2 mg/kg (ketanserin + amlodipine), the combination possessed the largest synergism on blood pressure reduction. In Experiments 2 and 3, SHR-SP and two-kidney, two-clip (2K2C) renovascular hypertensive rats received life-long treatments with ketanserin (1 mg/kg) and amlodipine (2 mg/kg) or their combination (0.5 + 1, 1 + 2, 2 + 4 mg/kg). The survival time was recorded and the brain lesion was examined. It was found that all kinds of treatments prolonged the survival time of SHR-SP and 2K2C rats. The combination possessed a significantly better effect on stroke prevention than mono-therapies. In conclusion, combination of blood pressure reduction and baroreflex restoration may be a new strategy for the prevention of stroke in hypertension.
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Affiliation(s)
- Shu-Wei Song
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
- Department of Nephrology, Changzheng Hospital, Kidney Center of PLA, Second Military Medical UniversityShanghai, China
| | - Ai-Jun Liu
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
| | - Chong Bai
- Department of Respiratory Diseases, Second Military Medical UniversityShanghai, China
| | - Bei-Lin Su
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
| | - Xiu-Juan Ma
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
| | - Fu-Ming Shen
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
| | - Jun-Li Duan
- Department of Gerontology, Xinhua Hospital, Shanghai Jiaotong UniversityShanghai, China
| | - Ding-Feng Su
- Department of Pharmacology, School of Pharmacy, Second Military Medical UniversityShanghai, China
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Sardine peptide with angiotensin I-converting enzyme inhibitory activity improves glucose tolerance in stroke-prone spontaneously hypertensive rats. Biosci Biotechnol Biochem 2009; 73:2203-9. [PMID: 19809178 DOI: 10.1271/bbb.90311] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An enzymatic hydrolysate of sardine protein (sardine peptide, SP) derived from sardine muscle possesses angiotensin I-converting enzyme (ACE) inhibitory activity. In the present study, we investigated the effect of SP on the blood glucose levels in stroke-prone spontaneously hypertensive rats (SHRSPs). Ten-week-old SHRSPs were assigned to three groups. The control group was given tap water for 4 weeks, while the experimental groups were given water containing SP (1 g/kg/d) or an ACE inhibitor, captopril (8 mg/kg/d). Treatment with SP and captopril decreased ACE activity in the kidney, aorta, and mesentery. There were no differences in fasting blood glucose levels among the three groups, whereas SP and captopril administration significantly suppressed the increase in blood glucose after glucose loading in the control SHRSPs. No difference was observed in plasma insulin levels among the three groups. Thus treatment with captopril and ACE-inhibitory sardine peptides ameliorated the glucose tolerance of this rat strain.
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