Effect of Chronic Clonidine Treatment and its Abrupt Cessation on Mean Blood Pressure of Rats with a Normal or An Elevated Blood Pressure

1979 ◽  
Vol 57 (2) ◽  
pp. 195-201 ◽  
Author(s):  
J. Atkinson ◽  
Nicole Boillat ◽  
Roselyne Pera-Bally ◽  
Lise Peters-Haefeli ◽  
E. J. Kirchertz
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Early Stage ◽  
Mean Blood Pressure ◽  
Average Dose ◽  
Elevated Blood ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Induced Hypertension ◽  
Drinking Fluid

1. Clonidine (6 mg of base/1 of water) was given as drinking fluid to normotensive rats or rats with established or early hypertension. 2. Spontaneous hypertensive rats (6 months old: average dose of clonidine, 0·6 mg 24 h−1 kg−1) showed a sustained fall in blood pressure over 3 weeks. 3. The same clonidine solution given for 6 weeks to two-kidney Goldblatt rats with early-stage hypertension (average dose of clonidine: 1 mg 24 h−1 kg−1) or spontaneously hypertensive rats (clonidine dose: 1 mg) induced a fall in mean blood pressure, but no change in normotensive rats. 4. Replacement of clonidine by water induced hypertension and lability which led to death in hypertensive but not in normotensive rats.

Abstract 69: Reduction of Diastolic Dysfunction by Treatment of a Combination of Agonists of Adenosine Receptor in Spontaneously Hypertensive Rats Submitted to Myocardial Infarction

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Gisele Zapata-Sudo ◽  
Tais N Frazão ◽  
Jaqueline S da Silva ◽  
Eliezer J Barreiro ◽  
Carlos A Fraga ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Volume Fraction ◽  
Left Ventricular ◽  
Mean Blood Pressure ◽  
Heart Weight ◽  
Hemodynamic Parameters ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive

Introduction: This work investigated the cardioprotective actions of the combination of a positive inotropic agent (LASSBio-294 ) and a potent vasodilator (LASSBio-897) in spontaneously hypertensive rats (SHR) submitted to myocardial infarction (MI). Methods: Twenty four SHR (180-200 g) were randomly divided in sham-operated (SO) and infarcted groups (MI) and each group subdivided in two: treatment with vehicle (DMSO) or with LASSBio-294 + LASSBio-897 (5mg/kg each, p.o.) during 8 weeks. After treatment period, the animals were submitted to echocardiography to determine the anterior wall thickness (AWT), ejection fraction (EF), fractional shortening (FS) and the ratio of early and late transmitral filling velocity (E/A). In addition, the following hemodynamic parameters were evaluated: mean blood pressure (MBP), left ventricular end diastolic pressure (LVEDP), left ventricular end-systolic pressure (LVESP) and LV contractility and relaxation (dp/dt max ). Hypertrophy was measured using the relation between heart weight to body weight (HW/BW). The volume fraction of collagen (%) was determined by measuring the area of H&E stained tissue within a given field. Results: MI induced in SHR promoted a decrease in AWT; EF; FS and E/A from 2.0 ± 0.4 to 1.6 ± 0.9 mm; from 53.1 ± 7.5 to 25.3 ± 6.4 %; from 40.0 ± 0.9 to 25.3 ± 11.0 %; and from 1.4 ± 0.1 to 0.9 ± 0.1, respectively. Treatment with the combination of drugs, increased AWT to 2.5 ± 0.6 mm; EF to 73.2 ± 1.0 %; FS to 43.5 ± 6.6%; and E/A to 1.3 ± 0.1. Increase of LVEDP from 4.6 ± 0.3 to 30.0 ± 3.6 mmHg and duplicated oxygen consumption were observed in MI-SHR. The negative dP/dt was reduced from 6152 ± 1015 to 3957 ± 1225 mm Hg/s. After treatment, all hemodynamic parameters were restored to values similar to SO group. Mean blood pressure which was increased after MI from 168. 2 ± 18.6 to 197.7 ± 10.7 returned to 137.0 ± 19.3 mm Hg after treatment. Increased deposition of colagen from 15.1 ± 3.9 to 24.0 ± 0.9 % induced by MI was prevented with treatment with the combination of drugs (12.9 ± 3.8 %). Conclusion: Oral administration of the combination of LASSBio-294 and LASSBio-897 could be considered promising in preventing cardiac dysfunction in SHR submitted to MI.

scholarly journals Electroacupuncture Delays Hypertension Development through Enhancing NO/NOS Activity in Spontaneously Hypertensive Rats

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Hye Suk Hwang ◽  
Yoo Sung Kim ◽  
Yeon Hee Ryu ◽  
Ji Eun Lee ◽  
Young Seop Lee ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Mesenteric Artery ◽  
Spontaneously Hypertensive Rats ◽  
Early Stage ◽  
Acupuncture Point ◽  
Hypertensive Rats ◽  
Treatment Control ◽  
Blood Pressure Elevation ◽  
Spontaneously Hypertensive

Using spontaneously hypertensive rats (SHR), this study investigated whether electroacupuncture (EA) could reduce early stage hypertension by examining nitric oxide (NO) levels in plasma and nitric oxide synthase (NOS) levels in the mesenteric resistance artery. EA was applied to the acupuncture point Governor Vessel 20 (GV20) or to a non-acupuncture point in the tail twice weekly for 3 weeks under anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY) rats, blood pressure was determined the day after EA treatment by the tail-cuff method. We measured plasma NO concentration, and evaluated endothelial NO syntheses (eNOS) and neuronal NOS (nNOS) protein expression in the mesenteric artery. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower after 3 weeks of GV20 treatment than EA at non-acupuncture point and no treatment control in SHR. nNOS expression by EA was significantly different between both WKY and no treatment SHR control, and EA at GV20 in SHR. eNOS expression was significantly high in EA at GV 20 compared with no treatment control. In conclusion, EA could attenuate the blood pressure elevation of SHR, along with enhancing NO/NOS activity in the mesenteric artery in SHR.

scholarly journals Biological response of spontaneously hypertensive rats to the streptozotocin administration

2008 ◽  
Vol 51 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Virginia Alice Vieira da Costa ◽  
Lucia Marques Vianna
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Biological Response ◽  
Hypertensive Rats ◽  
Citrate Buffer ◽  
Spontaneously Hypertensive ◽  
Physiological Alterations ◽  
Drug Choice ◽  
Induced Hypertension

The sensitivity of adult spontaneously hypertensive rats (SHR) to the diabetogenic effect of streptozotocin (STZ) was studied. The animals were subdivided into three groups: control (citrate buffer), streptozotocin 40 mg/kg or 50 mg/kg, and general biologic parameters were analyzed, in addition to systolic blood pressure, blood glucose and insulin levels determinations. Both doses were able to induce hyperglycemia above 300 mg/dl; however, 50 mg/kg provoked a more pronounced physiological alterations in body weight, diuresis, water and food intake. There was no change on systolic blood pressure with either dose. Results suggested that SHRs did not need doses of streptozotocin above 40mg/kg in order to produce diabetes probably because this strain was much more sensible than normotensive rats. In addition, streptozotocin might be a drug choice to induce diabetes without provoking alterations in the blood pressure which allowed the use of this experimental model in the studies of induced hypertension-diabetes.

scholarly journals Slowing down of chronic renal failure progression with captopril in spontaneously hypertensive rats with adriamycin nephropathy

2002 ◽  
Vol 130 (3-4) ◽  
pp. 73-80 ◽  
Author(s):  
Dijana Jovanovic ◽  
Djurdjica Jovovic ◽  
Jasmina Varagic ◽  
Jovan Dimitrijevic ◽  
Zorica Dragojlovic ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Early Stage ◽  
Systemic Blood Pressure ◽  
Hypertensive Rats ◽  
Systemic Blood ◽  
Spontaneously Hypertensive ◽  
Functional Changes ◽  
Slowing Down ◽  
Adriamycin Nephropathy

In SHRs with ADR nephropathy treatment with captopril normalized systemic blood pressure, and slowed down CRF progression in their early stage. These functional changes correlate with significant slowing of glomerular and interstitial changes.

Effects of antiserum against alpha-rat atrial natriuretic polypeptide in spontaneously hypertensive rats

1989 ◽  
Vol 257 (4) ◽  
pp. H1104-H1109 ◽  
Author(s):  
A. Sasaki ◽  
O. Kida ◽  
T. Kita ◽  
J. Kato ◽  
S. Nakamura ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Spontaneously Hypertensive Rats ◽  
Physiological Role ◽  
Mean Blood Pressure ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Significant Difference

To clarify the physiological role of endogenous atrial natriuretic polypeptide (ANP), we investigated the effects of specific rabbit antiserum against alpha-rat ANP (alpha-rANP) on hemodynamics, diuresis, and natriuresis in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Intravenous administration of anti-alpha-rANP antiserum caused an obvious rise of mean blood pressure and cardiac output in both SHR and WKY compared with rats administered with normal rabbit serum. Although there was no significant difference in increments of mean blood pressure between SHR and WKY, the increment of cardiac output in SHR was significantly higher than that in WKY. On the other hand, significant reductions in urine output and urinary sodium and potassium excretion lasted for approximately 20 min after administration of the antiserum in both SHR and WKY compared with rats administered with normal rabbit serum. There was no significant difference in these initial maximal decrements between SHR and WKY. These results indicate that endogenous ANP has an important physiological role in the regulation of hemodynamics and water-electrolyte balance in both SHR and WKY. The greater increment of cardiac output in SHR in response to the antiserum suggests that endogenous ANP in SHR may have a stronger cardiosuppressive action that it does in WKY.

scholarly journals Effect of Chinese Medicine Xinmaitong on Blood Pressure in Spontaneously Hypertensive Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Bin Zhang ◽  
Dong Li ◽  
Gexiu Liu ◽  
Wenfeng Tan ◽  
Jun Guo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Treatment Group ◽  
Protein Expression ◽  
Spontaneously Hypertensive Rats ◽  
Early Stage ◽  
Control Group ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Protein Levels ◽  
Mrna And Protein Expression

Objective. To investigate the effect of traditional Chinese antihypertensive compound Xinmaitong on blood pressure and vasoactive factors of vasoconstrictor endothelin-1 (ET-1) and vasodilator calcitonin gene related peptide (CGRP) in spontaneously hypertensive rats (SHRs) with early stage hypertension. Methods. Twenty male SHRs were randomly divided into two groups: 10 for hypertensive control group and 10 for hypertensive treatment group. In addition, 10 Wistar rats were used as the normal control group without any intervention. SHRs of hypertensive treatment group were orally treated with Xinmaitong, while the hypertensive control group was treated with the normal saline (NS) for a total of eight weeks. The blood pressure in SHRs was examined before and after the end of the eight-week study. After treatment, the rats were killed and the blood samples were collected to measure plasma levels of ET-1 and CGRP by ELISA method, respectively. Meanwhile, the aorta rings were isolated for measuring the mRNA expression of ET-1 and CGRP by PCR. Moreover, the protein levels of ET-1 and CGRP were studied by immunohistochemical. Results. Daily oral administration of Xinmaitong resulted in significant fall in the SHRs’ blood pressure, including systolic and diastolic blood pressures (SBP and DBP), mean blood pressure (MBP), and pulse pressure (PP). The plasma ET-1 levels were reduced and CGRP increased. In parallel, the mRNA and protein expression of ET-1 were decreased, whereas the mRNA and protein expression of CGRP were enhanced in SHRs treated with Xinmaitong. Conclusion. The present study demonstrated for the first time that Xinmaitong leads to the fall in blood pressure of SHRs and that this antihypertensive effect is, at least in part, due to improvement of arterial tone.

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