To investigate the mechanisms underlying the cholinergic agonist carbachol-induced cardiovascular responses, changes of renin-angiotensin system were examined in fetal hormonal systems. In the ovine fetal model under stressless condition, the cardiovascular function was recorded. Blood samples were collected before (during baseline period) and after the intravenous administration of carbachol. Simultaneously, the levels of angiotensin I (Ang I), angiotensin II (Ang II) and vasopressin in the fetal plasma were detected by immunoradiological method. Also, blood gas, plasma osmolality and electrolyte concentrations were analyzed in blood samples. Results showed that in chronically prepared ovine fetus, intravenous infusion of carbachol led to a significant decrease of heart rate (P < 0.05), and a transient decrease followed by an increase of blood pressure (P < 0.05) within 30 min. After the intravenous infusion of carbachol, blood concentrations of Ang I and Ang II in near-term ovine fetus were both significantly increased (P < 0.05); however, blood concentration of vasopressin, values of blood gas, electrolytes and plasma osmolality in near-term ovine fetus were not significantly changed (P > 0.05). Blood levels of Ang I and Ang II in the atropine (M receptor antagonist) + carbachol intravenous administration group was lower than those in the carbachol group without atropine administration (P < 0.05). In conclusion, this study indicates that the near-term changes of cardiovascular system induced by intravenous administration of carbachol in ovine fetus, such as blood pressure and heart rate, are associated with the changes of hormones of circulatory renin-angiotensin system.
Angiotensin I ; blood ; Angiotensin II ; blood ; Animals ; Blood Pressure ; Carbachol ; pharmacology ; Cholinergic Agonists ; pharmacology ; Fetus ; Heart Rate ; Renin-Angiotensin System ; Sheep ; Vasopressins ; blood

BACKGROUND: Prostaglandin system is known to participate in manifestation of the renin-angiotensin system. However, role of prostaglandins on the renin-angiotensin system in development of hypertension is not well established. This study was to examine whether the role of prostaglandins is altered in experimental hypertension. METHODS: Two-kidney, one-clip(2KIC) renal hypertension was made by clipping the left renal artery with a silver clip(internal gap of 0.2mm) and deoxycorticosterone acetate (DOCA)-salt hypertension by subcutaneous implantation of DOCA(200mg/kg) strip plus saline(1%) drinking. They were used 3 weeks later. Age-matched normal rats served as a control. Femoral artery was cannulated and arterial blood pressure and heart rate were monitored continuously. RESULTS: 1) In normotensive rats, saralasin infusion(20 microg/kg/min, IV) caused a decrease in mean arterial pressure without significant alterations in heart rate. Indomethacin-pretreatment(10mg/kg, IP) abolished the depressor response to saralasin. 2) The depressor response to saralasin was more marked in renal hypertensive rats than in normotensive rats. The magnitude of maximum decrease in blood pressure, however, was comparable between the hypertensive and normotensive rats. Indomethacin-pretreatment did not affect the depressor response to saralasin in renal hypertensive rats. 3) In DOCA-salt hypertensive rats, saralasin infusion rather caused an increase in mean arterial pressure without significant alterations in heart rate. The pressor response to saralasin was not affected by indomethacin-pretreatment. CONCLUSION: These results indicate that prostaglandin system may modify renin-angiotensin system in normotensive rats. It is suggested that mechanisms other than prostaglandin system participate in the full-blown manifestation of renin-angiotensin system in 2KIC renal hypertensive rats.
Animals ; Arterial Pressure ; Blood Pressure ; Desoxycorticosterone ; Drinking ; Femoral Artery ; Heart Rate ; Hypertension ; Hypertension, Renal ; Prostaglandins I ; Prostaglandins* ; Rats* ; Renal Artery ; Renin-Angiotensin System* ; Saralasin ; Silver

OBJECTIVETo investigate effects of angiotensin (1-7) [Ang (1-7)] and enalaprilat on function of isolated rat heart perfused by burn serum.

METHODSEighty SD rats were used to prepare burn serum. Hearts of another 24 SD rats were isolated to reproduce Langendorff perfusion model. The rat hearts were divided into different groups with different perfusion fluids as K-H buffer group, K-H buffer containing 20% burn serum group (burn serum group), K-H buffer containing 20% burn serum and 2 microg/mL enalaprilat group (enalaprilat group), and K-H buffer containing 20% burn serum and 1 nmol/mL Ang (1-7) group [Ang(1-7) group]. The rat hearts were perfused for 30 mins with each of above-mentioned fluids in different groups. Then left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), +/- dp/dt max, coronary flow(CF), level of creatine kinase (CK) and lactate dehydrogenase (LDH) in respective coronary effluent were determined.

RESULTSCompared with LVSP (11.2 +/- 1.0 kPa, 1 kPa = 7.5 mm Hg), +dp/dt max (642 +/- 53 kPa/s), -dp/dt max (380 +/- 61 kPa/s) and CF level in K-H buffer group, CF, LVSP (5.9 +/- 0.8, 8.0 +/- 1.1, 8.9 +/- 1.3 kPa, respectively), +dp/dt max (275 +/- 37, 454 +/- 48, 479 +/- 63 kPa/s, respectively), -dp/dt max (135 +/- 35, 219 +/- 47, 277 +/- 58 kPa/s, respectively) of burn serum group, those levels in Ang (1-7) group, and enalaprilat group were decreased obviously (P < 0.05 or P < 0.01), but LVEDP, level of CK and LDH in coronary effluent were increased. Compared with those parameters in burn serum group, CF, LVSP, +/- dp/dt max of Ang (1-7) group and enalaprilat group were increased obviously (P < 0.05 or P < 0.01), and LVEDP, level of CK and LDH in coronary effluent were decreased obviously (P < 0.01).

CONCLUSIONSAng (1-7) and enalaprilat can effectively improve left ventricular function of isolated rat heart perfused by burn serum and mitigate myocardial injury.

Angiotensin I ; pharmacology ; Animals ; Burns ; blood ; Enalaprilat ; pharmacology ; Male ; Myocardial Reperfusion Injury ; prevention & control ; Peptide Fragments ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Serum ; Ventricular Function, Left ; drug effects

Angiotensin I ; pharmacology ; Animals ; Blood Pressure ; drug effects ; physiology ; Infusions, Intraventricular ; Male ; Peptide Fragments ; pharmacology ; Pulmonary Artery ; physiology ; Rats ; Rats, Sprague-Dawley

BACKGROUND AND OBJECTIVES: The renin angiotensin system seems to play an important role in the development of cardiac and vascular hypertrophy in hypertension. The changes in pathology, and gene expressions of the angiotensin II receptor type 1A (ATIA) and angiotensin converting enzyme (ACE) were investigated in order to explore the effects of losartan in spontaneously hypertensive rat (SHR) models. MATERIALS AND METHODS: Twelve week-old male Wistar rats were grouped as follows: control (C) group, hypertension (H) group, and losartan (L) group in which SHR was treated with losartan (10 mg/kg/day). Western blot and reverse transcription-polymerase chain reaction analysis regarding seven genes such as endothelin-1, ACE, ATIA, neutrophil cytosolic factor, brain natriuretic peptide, troponin I, endothelial nitric oxide synthase were performed. RESULTS: Systolic blood pressure was significantly decreased in the L group compared with the H group in weeks 3 and 5. ACE and ATIA proteins in the L group were lower than H group in week 5. CONCLUSION: Losartan reduced blood pressure, cardiac hypertrophy and protein expressions of ACE and ATIA. Changes of protein expressions were more sensitive than changes in pathology. Further study is needed for the differing doses of losartan in SHR models.
Blood Pressure ; Blotting, Western ; Cardiomegaly ; Cytosol ; Endothelin-1 ; Gene Expression ; Humans ; Hypertension ; Hypertrophy ; Losartan ; Male ; Natriuretic Peptide, Brain ; Neutrophils ; Nitric Oxide Synthase Type III ; Peptidyl-Dipeptidase A ; Proteins ; Rats, Inbred SHR ; Rats, Wistar ; Receptors, Angiotensin ; Renin-Angiotensin System ; Troponin I

OBJECTIVE: Silicosis, caused by inhalation of silica dust, is the most serious occupational disease in China and the aim of present study was to explore the protective effect of Ang (1-7) on silicotic fibrosis and myofibroblast differentiation induced by Ang II. METHODS: HOPE-MED 8050 exposure control apparatus was used to establish the rat silicosis model. Pathological changes and collagen deposition of the lung tissue were examined by H.E. and VG staining, respectively. The localizations of ACE2 and α-smooth muscle actin (α-SMA) in the lung were detected by immunohistochemistry. Expression levels of collagen type I, α-SMA, ACE2, and Mas in the lung tissue and fibroblasts were examined by western blot. Levels of ACE2, Ang (1-7), and Ang II in serum were determined by ELISA. Co-localization of ACE2 and α-SMA in fibroblasts was detected by immunofluorescence. RESULTS: Ang (1-7) induced pathological changes and enhanced collagen deposition in vivo. Ang (1-7) decreased the expressions of collagen type I and α-SMA and increased the expressions of ACE2 and Mas in the silicotic rat lung tissue and fibroblasts stimulated by Ang II. Ang (1-7) increased the levels of ACE2 and Ang (1-7) and decreased the level of Ang II in silicotic rat serum. A779 enhanced the protective effect of Ang (1-7) in fibroblasts stimulated by Ang II. CONCLUSION Ang (1-7) exerted protective effect on silicotic fibrosis and myofibroblast differentiation induced by Ang II by regulating ACE2-Ang (1-7)-Mas axis.
Actins ; metabolism ; Angiotensin I ; blood ; pharmacology ; therapeutic use ; Angiotensin II ; blood ; Animals ; Animals, Newborn ; Cell Differentiation ; drug effects ; Cells, Cultured ; Collagen Type I ; metabolism ; Disease Models, Animal ; Lung ; metabolism ; pathology ; Myofibroblasts ; drug effects ; Peptide Fragments ; blood ; pharmacology ; therapeutic use ; Peptidyl-Dipeptidase A ; metabolism ; Rats, Wistar ; Silicosis ; metabolism ; pathology ; prevention & control

The effect of NaCl plus 3% chitosan on the systolic blood pressure of spontaneously hypertensive rats (SHR) were evaluated and compared with NaCl plus KCl (NaCl, 49.36% + KCl 49.36%) and chitosan or NaCl treatment alone. In SHR, administration of NaCl plus chitosan (44 mM Na/day) for two months significantly decreased the systolic blood pressure greater than of NaCl plus KCl and NaCl alone. NaCl plus chitosan resulted, though not statistically significant, in decreased urinary Na+ excretion and decreased blood urea nitrogen levels. Urinary creatinine of NaCl plus chitosan was slightly decreased compared to 3 treated groups. Serum electrolytes levels, however, remained unchanged. The combination of NaCl and chitosan may be superior to the conventional use of NaCl plus KCl or NaCl alone in the prevention of hypertension. Even though these supplementary diets have demonstrated potential anti-hypertensive effects in the experimental animal model, further research is needed before any recommendations can be made.
Angiotensin I/blood ; Angiotensin II/biosynthesis ; Animals ; Blood Pressure/*drug effects/physiology ; Blood Urea Nitrogen ; Body Weight/drug effects ; Chitosan/*administration & dosage ; Chlorides/blood/urine ; Creatinine/urine ; Heart/physiology ; Histocytochemistry ; Hypertension/*prevention & control ; Kidney/physiology ; Male ; Potassium/blood/urine ; Potassium Chloride/administration & dosage ; Random Allocation ; Rats ; Rats, Inbred SHR ; Sodium/blood/urine ; Sodium Chloride, Dietary/*administration & dosage ; Systole/drug effects/physiology

OBJECTIVETo investigate the effect of tanshinone II(A) on the expression of different components in the renin-angiotensin system of left ventricles of renal hypertensive rats.

METHODThe renal hypertension model was established in rats by the two-kidney-one-clip (2K1C) method. In the experiment, all of the rats were randomly divided into four groups (n = 15 per group) before the operation: the sham-operated (Sham) group, the hypertensive model (Model) group, the low-dose tanshinone II(A) group and the high-dose tanshinone II(A) group. At 5 week after the renal artery narrowing, the third and fourth groups were administered with 35 mg kg(-1) x d(-1) and 70 mg x kg(-1) x d(-1) of tanshinone II(A), respectively. The blood pressure in rats was determined by the standard tail-cuff method in each week after the operation. After the drug treatment for 8 weeks, all the rats were put to death, and their left ventricles were separated to determine the ratio of left ventricle weight to body weight (LVW/BW), the myocardial collagen content, and the expressions of different components in myocardial RAS, including angiotensin converting enzyme (ACE), angiotensin converting enzyme 2 (ACE2), angiotensin 1-type receptor (AT1R), Mas receptor mRNA expression and angiotensin II (Ang II) and angiotensin (1-7) [Ang (1-7)] content.

RESULTCompared with the sham group, the hypertensive model group exhibited a markable increase in the content of Ang II and Ang (1-7) and the mRNA expressions of ACE, ACE2, AT1R and Mas (P < 0.01). However, the treatment with tanshinone II(A) showed the does dependence, inhibited left ventricle hypertrophy, decreased myocardial Ang II content and the mRNA expression of ACE and AT, R in renal hypertensive rats (P < 0. 01) , further increased the myocardial Ang (1-7) content and the mRNA expression of ACE2 and Mas (P < 0.01) , but without any change in the blood pressure of hypertensive rats.

CONCLUSIONThe treatment with tanshinone II(A) could inhibit left ventricle hypertrophy of renal hypertensive rats. Its mechanism may be partially related to the expression of different components in the renin-angiotensin system for regulating myocardial tissues.

Angiotensin I ; genetics ; metabolism ; Angiotensin II ; genetics ; metabolism ; Animals ; Blood Pressure ; drug effects ; Diterpenes, Abietane ; administration & dosage ; Heart Ventricles ; drug effects ; metabolism ; Humans ; Hypertension ; drug therapy ; genetics ; metabolism ; physiopathology ; Male ; Peptide Fragments ; genetics ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Renin ; genetics ; metabolism ; Renin-Angiotensin System ; drug effects

OBJECTIVETo investigate the effect of losartan on prostatic hyperplasia in spontaneous hypertension rats (SHRs) and its pathophysiological mechanism.

METHODSWe randomly divided 36 male SHRs into three groups of equal number to be treated intragastrically with high-dose losartan (30 mg per kg per d), low-dose losartan (15 mg per kg per d) and distilled water (control group). After 6 weeks of intervention, we measured the body weight and tail artery blood pressure of the rats and compared them with the baseline data. We collected blood from the heart for determination of the levels of serum angiotensin II (Ang II), insulin-like growth factor-1 (IGF-1) and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay (ELISA), and harvested their prostates for measurement of their weight, observation of the tissue ultrastructures under the electron microscope and detection of the expression of endothelial nitric oxide synthase (eNOS) in the prostate tissue by immunohistochemistry.

RESULTSCompared with the control group, the low- and high-dose losartan groups showed significant decreases in systolic blood pressure ([203.75 +/- 10.28] vs [184.54 +/- 16.90] mmHg, P = 0.013; [203.75 +/- 10.28] vs [166.88 +/- 14.74] mmHg, P = 0.001) and diastolic blood pressure ([151.58 +/- 9.96] vs [136.71 +/- 14.28] mmHg, P = 0.022; [151.58 +/- 9.96] vs [122.71 +/- 11.56] mmHg, P < 0.001) of the lower tail artery after treatment, as well as in the prostate weight ([0.73 +/- 0.08] vs [0.64 +/- 0.10] mg, P = 0.011; [0.73 +/- 0.08 ] vs [0.50 +/- 0.17] mg, P < 0.001). Electron microscopy revealed edema of the basal and columnar epithelial cells, concentrated and marginated heterochromatin and widened nuclear gap of interstitial fibroblast nuclei, and reduced mitochondria and endoplasmic reticula in the low-dose losartan group, and even more obvious in the high-dose group. The level of serum Ang II was remarkably higher in the low- and high-dose losartan groups than in the control ([61.32 +/- 2.49] vs [54.85 +/- 7.20] pg/ml, P = 0.021; [65.49 +/- 6.78] vs [54.85 +/- 7.20] pg/ml, P < 0.001]) , that of serum IGF-1 was lower in high-dose losartan than in the control group ([1.50 +/- 0.11] vs [1.60 +/- 0.10] ng/ml, P = 0.03), but the serum IL-6 levels exhibited no significant differences among the three groups. The expression of eNOS in the prostate tissue was significantly higher in the losartan groups than in the controls (P = 0.022), even higher in the high-dose than in the low-dose group.

CONCLUSIONLosartan can suppress the progression of prostate hyperplasia in spontaneous hypertension rats by inhibiting RAS, IGF-1 and angiogenesis.

Angiotensin II ; blood ; Animals ; Antihypertensive Agents ; pharmacology ; therapeutic use ; Hypertension ; drug therapy ; metabolism ; pathology ; Insulin-Like Growth Factor I ; metabolism ; Interleukin-6 ; blood ; Losartan ; pharmacology ; therapeutic use ; Male ; Nitric Oxide Synthase Type III ; metabolism ; Prostate ; drug effects ; metabolism ; pathology ; Prostatic Hyperplasia ; drug therapy ; metabolism ; pathology ; Rats ; Rats, Inbred SHR

To study the expression of angiotensin converting enzyme 2 (ACE2) and angiotensin (Ang) 1-7 specific receptor Mas protain in renal blood vessels of metabolic syndrome ( MS) rats and its anti-oxidative effect. A total of 80 male SD rats were divided into four groups: the normal control group (NC, the same volume of normal saline), the MS group (high fat diet), the MS + Astragali Radix group (MS + HQ, 6 g x kg(-1) x d(-1) in gavage) and the MS + Valsartan group (MS + XST, 30 mg x kg(-1) x d(-1) in gavage). After four weeks of intervention, their general indexes, biochemical indexes and blood pressure were measured; plasma and renal tissue Ang II, malondialdehyde (MDA) and superoxide demutase (SOD) levels were measured with radioimmunoassay. The protein expressions of Mas receptor, AT1R, ACE and ACE2 were detected by western blot analysis. According to the result, compared with the NC group, the MS group and the MS + HQ group showed significant increases in systolic and diastolic pressures, body weight, fasting glucose, fasting insulin, triglycerides, free fatty acid and Ang II level of MS rats (P < 0.05). The MS + XST group showed notable decreases in systolic and diastolic pressures than that of the MS group. The MS group showed significant increases in the SOD activity and NO level and decrease in the MDA level after being intervened with Astragali Radix. ACE and AT1R protein expressions in renal tissues of the MS group were higher than that in the NC group, but with lower ACE2 and -Mas receptor expressions (all P < 0.05). Compared with the MS group, the MS + HQ group showed significant increase in Mas receptor expression in renal tissues, whereas the MS + XST group showed notable decrease in AT1R (all P < 0.05). In conclusion, Astragali Radix can increase the Mas receptor expressions in renal tissues, decrease ACE expression and change local Ang II, MDA, NO and SOD in kidneys, so as to protect early damages in renal tissues.
Angiotensin I ; metabolism ; Animals ; Astragalus Plant ; chemistry ; Blood Glucose ; metabolism ; Blood Pressure ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Kidney ; drug effects ; injuries ; metabolism ; Male ; Malondialdehyde ; metabolism ; Metabolic Syndrome ; drug therapy ; genetics ; metabolism ; physiopathology ; Peptide Fragments ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Signal Transduction ; drug effects