• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.327-335
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• 2009

The aim of this study was to determine whether losartan, an angiotensin II (Ang II) type 1 ($AT_1$) receptor could influence the CA release from the isolated perfused model of the rat adrenal medulla. Losartan (5${\sim}$50 ${\mu}$M) perfused into an adrenal vein for 90 min produced dose- and time-dependent inhibition of the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM, a direct membrane depolarizer), DMPP (100 ${\mu}$M) and McN-A-343 (100 ${\mu}$M). Losartan failed to affect basal CA output. Furthermore, in adrenal glands loaded with losartan (15 ${\mu}$M) for 90 min, the CA secretory responses evoked by Bay-K-8644 (10 ${\mu}$M, an activator of L-type $Ca^{2+}$ channels), cyclopiazonic acid (10 ${\mu}$M, an inhibitor of cytoplasmic $Ca^{2+}$ -ATPase), veratridine (100 ${\mu}$M, an activator of $Na^+$ channels), and Ang II (100 nM) were markedly inhibited. However, at high concentrations (150${\sim}$300 ${\mu}$M), losartan rather enhanced the CA secretion evoked by ACh. Collectively, these experimental results suggest that losartan at low concentrations inhibits the CA secretion evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization from the rat adrenal medulla, but at high concentration it rather inhibits ACh-evoked CA secretion. It seems that losartan has a dual action, acting as both agonist and antagonist to nicotinic receptors of the rat adrenal medulla, which might be dependent on the concentration. It is also thought that this inhibitory effect of losartan may be mediated by blocking the influx of both $Na^+$ and $Ca^{2+}$ into the rat adrenomedullary chromaffin cells as well as by inhibiting the $Ca^{2+}$ release from the cytoplasmic calcium store, which is thought to be relevant to the $AT_1$ receptor blockade, in addition to its enhancement of the CA release.

• The Korean Journal of Physiology and Pharmacology
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• 제19권4호
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• pp.299-307
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• 2015

Severe acute pancreatitis (SAP) is normally related to multiorgan dysfunction and local complications. Studies have found that local pancreatic renin-angiotensin system (RAS) was significantly upregulated in drug-induced SAP. The present study aimed to investigate the effects of angiotensin II receptors inhibitor valsartan on dual role of RAS in SAP in a rat model and to elucidate the underlying mechanisms. 3.8% sodium taurocholate (1 ml/kg) was injected to the pancreatic capsule in order for pancreatitis induction. Rats in the sham group were injected with normal saline in identical locations. We also investigated the regulation of experimentally induced SAP on local RAS expression in the pancreas through determination of the activities of serum amylase, lipase and myeloperoxidase, histological and biochemical analysis, radioimmunoassay, fluorescence quantitative PCR and Western blot analysis. The results indicated that valsartan could effectively suppress the local RAS to protect against experimental acute pancreatitis through inhibition of microcirculation disturbances and inflammation. The results suggest that pancreatic RAS plays a critical role in the regulation of pancreatic functions and demonstrates application potential as AT1 receptor antagonists. Moreover, other RAS inhibitors could be a new therapeutic target in acute pancreatitis.

• The Korean Journal of Physiology and Pharmacology
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• 제6권3호
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• pp.149-154
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• 2002

The blood pressure (BP) is regulated by the nervous system and humoral factors, such as renin- angiotensin system, vasopressin and others. In the present study, we examined the central effects of glutamate and GABA on the cardiovascular regulation by injection of these substances into the lateral ventricle and also investigated the relationship between these central effects and the action of angiotensin II (Ang). Male Sprague Dawley rats, $350{\sim}400$ g, were anesthetized with urethane and instrumented with an arterial catheter for direct measurement of BP and heart rate (HR), and an guide cannula in the lateral ventricle for drug injection. A glass microelectode was inserted into the rostral ventrolateral medulla (RVLM) for recording single unit spikes. Barosensitive neurons were identified by changes of single unit spikes in RVLM following intravenous injection of nitroprusside and phenylephrine. The effects of GABA and glutamate injected into the lateral ventricle were studied in single neuronal activity of the RVLM in addition to changes in BP and heart rate, and compared the results before and after treatment with intravenous losartan, nonpeptide Ang II-type 1 receptor antagonist (1 mg/100 g BW). Intracerebroventricular administration of GABA decreased systolic blood pressure (SBP) and HR, but increased the firing rates in the RVLM. However, intracerebroventricular glutamate injection produced effects opposite to GABA. After pretreatment of intravenous losartan, the central effects of GABA on BP and firing rate in the RVLM were significantly attenuated and that of glutamate showed a tendency of attenuation. These results suggested that central GABA and glutamate regulated BP and firing rates in RVLM were inversely related to BP change. The central effects of GABA or glutamate on the autonomic nervous function were modulated by humoral factor, Ang II, by maintaining BP.

• 한국임상약학회지
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• 제27권3호
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• pp.136-142
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• 2017

Background: Dementia is one of important social and economic healthcare issues in the aging age. Therefore, it signifies to analyze the relationship between chronic disease or cardiovascular drug use and the incidence of dementia to establish a basis for increasing or preventing the risk of dementia. The purpose of this study was to investigate the correlation between the prevalence of chronic diseases and the use of cardiovascular drugs in patients diagnosed with dementia. Methods: In this study, we used data from sample of elderly patients from the Health Insurance Review and Assessment Service. We analyzed by logistic regression analysis with age, gender, and medication as covariates. KCD-7 was used to diagnosis of the disease, and drugs were analyzed using ATC codes and Korean standardized drug classification codes. Results: A total of 1,276,331 patients were analyzed in the sample of the elderly population, of which 532,075 (41.7%) were male and 744,256 (58.3%) were female. The patients have the higher risk of dementia in the older, women, and lower socioeconomically status. Cerebral infarction and ischemic heart disease increases risk of dementia. Patients taking statins, angiotensin converting enzyme inhibitor (ACEI) or angiotensin II receptor antagonists (ARB) showed low incidence of dementia. Conclusion: This study has been shown that ACEI, ARB, and statin drugs may associate with lower incidence of Alzheimer's and other dementia except vascular dementia.

• 한국임상수의학회지
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• 제38권4호
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• pp.189-193
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• 2021

An 11-years old spayed female Persian chinchilla cat presented with acute onset of blindness from bilateral retinal detachment and systemic hypertension. On physical examination, the cat was tachycardic (240 beats/min) with a systolic blood pressure of around 250 mmHg. Clinical findings, blood works, urinalysis, thyroid function test, radiography, echocardiogram, and ultrasonography were performed to rule out underlying diseases. Organ injury induced by systemic hypertension including bilateral retinal detachment and left ventricular hypertrophy were confirmed by ultrasound. Based on these results, it was diagnosed as feline idiopathic hypertension with target organ damage (TOD). The cat was treated with a combination therapy using high doses of amlodipine, telmisartan, and atenolol. After the treatment, its hypertension and TOD were improved. This case showed that appropriate therapeutic management can help prevent TOD associated with feline hypertension.

• The Korean Journal of Physiology and Pharmacology
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• 제1권2호
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• pp.151-159
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• 1997

In an attempt to investigate whether hemorrhage affects the gene expression of the renin-angioteusin system (RAS) components in the brain and peripheral angiotensin-generating tissues, changes in mRNA levels of the RAS components in response to hemorrhage were measured in conscious unrestrained rats. Wistar rats were bled at a rate of 3 ml/kg/min for 5 min, and then decapitated 7 h after hemorrhage. Levels of mRNA for renin, angiotensinogen and angiotensin $II-AT_1$ receptor subtypes ($AT_{1A}$ and $AT_{1B}$) were determined with the methods of northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR). Hemorrhage produced a profound hypotension with tachycardia, but blood pressure and heart rate recovered close to the basal level at 7 h. Plasma and renal renin levels were significantly increased at 7 h. Hemorrhage induced rapid upregulation of gene expression of both $AT_{1A}$ and $AT_{1B}$ receptor subtypes in the brainstem and hypothalamus, downregulation of them in the adrenal gland and liver. However, renin mRNA level increased in the brainstem, decreased in the liver, but was not changed in the hypothalamus, kidney and adrenals after hemorrhage. Angiotensinogen mRNA level was not significantly changed in any of the tissue except a slight increase in the liver. The kidney and liver did not show any significant change in gene expression of the RAS components. These results suggest that gene expression of the RAS in central and peripheral tissues are, at least in part, under independent control and the local RAS in each organ plays specific physiologic role.

• Childhood Kidney Diseases
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• 제24권1호
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• pp.36-41
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• 2020

Purpose: Hepatitis B virus (HBV) infection is among etiologies of secondary membranous nephropathy (MN) in pediatric patients. We evaluated expression of phospholipase A2 receptor (PLA2R), a specific target antigen of primary MN, in pediatric HBV-related MN. Methods: We retrospectively reviewed patients with biopsy-proven HBV-related MN from the renal biopsy registry and electronic medical records of Severance Hospital, Seoul, Korea, from 1993 to 2004. Paraffin-embedded human kidney tissues were retrieved and immunohistochemically stained for PLA2R. Results: Ten pediatric patients with 13 biopsied specimens were reviewed. The predominant pathological stage was stage II-III, and second was stage II. The intensity of staining for IgG was greatest, with less intense staining for IgM, IgA, C3, C4, and C1q. All the patients had angiotensin-converting enzyme inhibitor combined with glucocorticoid, and four patients converted to cyclosporine treatment from glucocorticoid monotherapy. Urinalysis of all the patients normalized after variable period. PLA2R staining was demonstrated in the outer glomerulus in 3 out of 13 biopsies, 2 of which were obtained from the same patient over a 5-year interval. Conclusions: PLA2R was expressed in a small number of cases diagnosed as pediatric HBV-related MN, indicating that some HBV-related MN cases may be primary MN concurrent with HBV infection.

• Childhood Kidney Diseases
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• 제7권1호
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• pp.52-59
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• 2003

목적 : 레닌-안지오텐신계는 신장의 성장과 발달에 중요한 역할을 하는 것으로 알려져 있으며, 안지오텐신 II는 신장형성기 동안 중요한 역할을 담당한다. 저자들은 터너 증후군 환자에서 신기형의 발생빈도를 조사하고, 신기형이 동반된 군과 동반되지 않은 군으로 분류하여 양군 사이에 레닌-안지오텐신계 유전자의 분포에 차이가 있는지를 조사하였다. 방법 : 말초혈액의 임파구를 사용하여 세포분 석학적 방법으로 진단된 33명의 터너 증후군 환자를 대상으로 신요로계의 기형여부를 초음파검사와 경정맥 요로 조영 검사, DMSA scan으로 진단하고, 더불어 안지오텐신전환효소의 유전자형, 안지오텐시노겐 유전자형, 안지오텐신 수용체유전자형의 분포를 핵산증폭법을 사용해 조사하였다. 결과 : 33명의 터너 증후군 환자 중 12명에서 신기형이 동반되어 전체적으로 36.4%의 빈도를 나타내었다. 핵형에 따른 신기형의 빈도를 살펴보면 전형적인 45,X형의 경우는 18명 중 8명에서 관찰되어 44.4%의 빈도를 나타내었고, 모자이시즘과 X 염색체구조상의 이상인 경우에는 15명 중 4명에서 관찰되어 26.7%의 빈도를 나타내어, 전형적인 45,X형의 경우에서 발생빈도가 높았으나 통계적으로 유의하지는 않았다(P>0.05). ACE 유전자형의 분포는 신기형 동반군에서 DD형이 0%, ID형이 73%, 그리고 II형이 27%이었으며, 신기형이 동반되지 않은 군에서는 DD형이 11%, ID형이 56%, II형이 33%로 양군 사이에는 ACE 유전자형의 분포는 유의한 차이가 없었다. AGT M235T 유전자형의 분포는 신기형 동반군에서 MM형이 82%, MT형이 8%, 그리고 TT형이 0%이었으며, 신기형이 동반되지 않은 군에서는 MM형이 56%, MT형이 33%, TT형이 11%로 양군 사이에는 AGT M235T 유전자형의 분포는 유의한 차이가 없었다. ATR 1 유전자형의 분포는 신기형 동반군에서 AA형이 91%, AC형이 9%, 그리고 CC형이 0%이었으며, 신기형이 동반되지 않은 군에서는 AA형이 94%, AC형이 6%, CC형이 0%로 양군 사이에는 ATR 1 유전자형의 분포도 유의한 차이가 없었다. 결론 : 터너증후군 환자에서 신기형의 동반율은 36.4%였으며, 45,X형에서 발생빈도가 높았으나 통계적으로 유의하지는 않았다. 신기형이 동반된 군과 동반되지 않은 군 사이에는 레닌-안지오텐신계 유전자의 분포는 모두 유의한 차이가 관찰되지 알았다.

• Biomolecules & Therapeutics
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• 제6권2호
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• pp.199-203
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• 1998

Acute hemodynamic effects of CJ-18513, a non-peptide angiotensin IIreceptor antagonist, were examined in mongrel dogs treated with high frequency ventricular pacing for one week. Rapid ventricular pacing reduced mean blood pressure (mBP), Lvdp/dt and cardiac output (CO), and increased the left ventricular end-diastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP). Continuous infusion of CJ-10513 at doses of 10 and 20$\mu$g/kg/min, respectively, for 30 minutes reduced mBP, LVEDP and myocardial oxygen consumption rate (MVO,) and shifted the cardiac function curve (CO-LVEDP ourve) to the left in this dog model. In conclusion, CJ-10513 decreased the preload and afterload and increased the cardiac function in dogs with pacing-induced heart failure.

• 한국축산식품학회지
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• 제44권3호
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• pp.533-550
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• 2024

Peptides with bioactive effects are being researched for various purposes. However, there is a lack of overall research on pork-derived peptides. In this study, we reviewed the process of obtaining bioactive peptides, available analytical methods, and the study of bioactive peptides derived from pork. Pepsin and trypsin, two representative protein digestive enzymes in the body, are hydrolyzed by other cofactors to produce peptides. Bicinchoninic acid assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, chromatography, and in vitro digestion simulation systems are utilized to analyze bioactive peptides for protein digestibility and molecular weight distribution. Pork-derived peptides mainly exhibit antioxidant and antihypertensive activities. The antioxidant activity of bioactive peptides increases the accessibility of amino acid residues by disrupting the three-dimensional structure of proteins, affecting free radical scavenging, reactive oxygen species inactivation, and metal ion chelating. In addition, the antihypertensive activity decreases angiotensin II production by inhibiting angiotensin converting enzyme and suppresses blood pressure by blocking the AT1 receptor. Pork-derived bioactive peptides, primarily obtained using papain and pepsin, exhibit significant antioxidant and antihypertensive activities, with most having low molecular weights below 1 kDa. This study may aid in the future development of bioactive peptides and serve as a valuable reference for pork-derived peptides.