THE DURATION OF THE FALL OF BLOOD PRESSURE FOLLOWING THE INDUCTION OF DECIDUOMATA AND THE ADMINISTRATION OF PROGESTERONE IN STEROID HYPERTENSIVE RATS

1970 ◽  
Vol 63 (2) ◽  
pp. 242-252 ◽  
Author(s):  
H. C. Moore ◽  
I. Cserhat ◽  
K. Wilson
Keyword(s):  
Blood Pressure ◽  
Hypotensive Effect ◽  
Related Phenomenon ◽  
Hypertensive Rats ◽  
Unknown Mechanism ◽  
Gland Cells ◽  
Hypotensive Episode ◽  
Metrial Gland ◽  
Main Effects

ABSTRACT Experimental deciduomata produce a protracted fall of blood pressure in steroid hypertensive rats. The fall begins at between 9 and 13 days of pseudopregnancy, lasts for between 8 and 14 days and is then followed by a restoration to higher levels between 17 and 24 days. The metrial gland of the deciduomata is thought to be responsible for the fall. Parenteral progesterone has two main effects. It enhances the degree of the fall of blood pressure and also prolongs the survival of deciduomata to beyond 22 days of pseudopregnancy. Progesterone does not alter the time of onset nor the duration of the hypotensive episode and the return of the blood pressure to higher levels takes place even though the metrial gland of the deciduomata is still viable and progesterone still being administered. It is considered that the duration of the hypotensive episode is determined either by a changed function of the metrial gland cells with duration or to an entirely different but unknown mechanism. The present findings suggest that the hypotensive effect of pregnancy in hypertensive rats is a related phenomenon and is due in part to the function of metrial gland cells of the pregnancy decidua under the influence of progesterone.

THE FALL OF BLOOD PRESSURE FOLLOWING INDUCTION OF DECIDUOMATA IN STEROID HYPERTENSIVE RATS RECEIVING PROGESTERONE

1968 ◽  
Vol 59 (2) ◽  
pp. 227-234 ◽  
Author(s):  
H. C. Moore ◽  
I. Cserhati ◽  
F. P. Biliczki
Keyword(s):  
Blood Pressure ◽  
Hypotensive Effect ◽  
Hypertensive Rats ◽  
Pregnant Rats ◽  
Hypertensive Rat ◽  
Equivalent Time ◽  
Metrial Gland ◽  
Blood Pressure Responses ◽  
A Minor ◽  
Maternal Decidua

ABSTRACT Experimental deciduomata and progesterone together lower the blood pressure in the steroid hypertensive rat from the 5th to 10th day of decidual growth i. e. from the 10th to 15th day of pseudopregnancy. This would suggest that the fall of blood pressure at an equivalent time of gestation in hypertensive pregnant rats could be due to the maternal decidua under the influence of progesterone. It is further considered that the metrial gland of the deciduoma is more likely to be responsible for the hypotensive effect and by comparison that the metrial gland is implicated in the hypotensive effect of pregnancy. Progesterone alone also exerts a minor hypotensive effect in those animals in which a nephrectomy forms part of the hypertension regimen and indicates one way in which a maternal renal factor could influence blood pressure responses in hypertensive pregnant rats.

THE EFFECT OF FOETAL REMOVAL ON THE BLOOD PRESSURE IN STEROID HYPERTENSIVE RATS

1971 ◽  
Vol 67 (3) ◽  
pp. 590-596 ◽  
Author(s):  
H. C. Moore ◽  
J. Borvendeg ◽  
K. Wilson
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Hypotensive Effect ◽  
The Other ◽  
Hypertensive Rats ◽  
Pregnancy Hypertension ◽  
Human Pregnancy ◽  
Other Hand ◽  
Metrial Gland

ABSTRACT In unilaterally nephrectomized hypertensive rats receiving DOCA, cortisone and saline the blood pressure falls after the removal of the foetuses as though the animals continued to be pregnant with the foetuses in situ. On the other hand, when the foetuses are removed from steroid hypertensive animals in which the maternal kidneys remain intact the blood pressure remains at hypertensive levels. The metrial gland part of the placenta appears histologically viable after foetal removal. We conclude from the present and earlier experiments that the usual hypotensive effect of pregnancy in hypertensive animals is due to a vasodepressor agent produced by the foetuses and the metrial gland moiety of the placenta and that the activity of this agent is subject to maternal renal function. A relation between these experiments and human pregnancy hypertension is not clear but we suggest that in human pregnancy, hypertension could be due either to failure of the foetoplacental vasodepressor or vasodilator agent or to destruction or excretion of this agent by the maternal kidney.

Abstract 181: Overexpression of Arachidonic Acid Cytochrome P450 Expoxygenases Prevents the Development of High Blood Pressure via Enhancing Atrial Natriuretic Peptide in Spontaneously Hypertensive Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Dao Wen Wang ◽  
Bin Xiao ◽  
Yong Wang ◽  
Xiaojun Xiong ◽  
Darryl C Zeldin
Keyword(s):  
Blood Pressure ◽  
Cytochrome P450 ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Spontaneously Hypertensive Rats ◽  
Hypotensive Effect ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Atrial Natriuretic

Cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) have potent vasodilatory and diuretic feature, and therefore potentially hypotensive effect. No in vivo studies, however, were performed to support it. This study investigated the hypothesis via overexpressing CYP epoxygense genes in spontaneously hypertensive rats (SHR). Recombinant adeno-associated virus vector (rAAV) was utilized to mediate long-term transfection of CYP2J2 and CYP2C11 genes, respectively, in adult SHR, and animal systolic blood pressure (SBP) was monitored using arterial caudilis indirect manometric method. Results showed that at 2 months the urinary excretion of stable hydrolysis metabolic product of 14, 15-EE, 14–15-DHET increased by 11 and 8.7 folds in rAAV-2J2 and rAAV-2C11 groups, respectively, compared with AAV-GFP-treated rats. (2) SBP in 2J2- and 2C11-treated rats decreased from 175.0 ± 2.8mHg to 163.5 ± 5.8mmHg and 161.2 ± 6.1 mmHg, respectively, ( p <0.01) at month 2, and it is 165.0 ± 4.7 mmHg and 173.0 ± 12.8 mmHg at month 6 after gene injection (~30mmHg and ~23mmHg lowerer than that in control animals, respectively, p <0.001). (3) Before the rats were sacrificed, cardiac function tests with Pressure-Volume System showed that maximum intracardiac pressure was 202.1 ± 30.0 & 209.1 ± 17.1mmHg in two gene-treated rats, respectively, significantly lower than control (241.2 ± 18.2mmHg, p <0.01) and cardiac output in treatment rats were significantly higher than control (p<0.05). (4) Interestingly, atrial natriuretic peptide (ANP) mRNA were up-regulated 6–14 folds respectively in myocardium of 2J2 and 2C11 groups; furthermore, C-type receptor mRNA of ANP was increased in heart, lung, kidney and aorta. (5) in cultured atrial cells (HLB2G5), exogenous EETs stimulated ANP production. In conclusions, for first time our data indicates overexpression of CYP2J2 or CYP2C11 could prevent development of hypertension in SHR, improve cardiac functions, which may involve up-regulating ANP expression and its receptors in target tissues, which suppresses collagen deposition and cardiovascular remodeling.

Hypotensive effect of water restriction in the two-kidney one-clip hypertensive rat

1981 ◽  
Vol 241 (5) ◽  
pp. F525-F531
Author(s):  
F. H. Leenen ◽  
W. de Jong
Keyword(s):  
Blood Pressure ◽  
Water Intake ◽  
Hypotensive Effect ◽  
Free Access ◽  
Water Restriction ◽  
Hypertensive Rats ◽  
Effect Of Water ◽  
Hypertensive Rat ◽  
Access To Water ◽  
Ad Libitum

In two-kidney one-clip hypertensive rats we evaluated the effect of water restriction on the development and maintenance of severe hypertension (systemic blood pressure 200-230 mmHg). After application of renal arterial clips in rats allowed access to water for 1 or 2 h daily, BP stabilized at 180-190 mmHg. No increase in water intake occurred and plasma renin activity(PRA) (measured before the drinking period) was significantly below the levels observed in ad libitum-drinking hypertensive rats. In rats administered 4 ml water/100 g body weight twice daily by gavage, development of hypertension was more clearly suppressed. Blood pressure increased slowly and reached levels of only 150-170 mmHg. Furthermore, PRA was significantly lower in this group compared with ad libitum-drinking hypertensive animals. In rats with established (4-5 wk) renal hypertension, restriction of water intake to 1 or 2 h daily resulted in a rapid decrease in BP of about 30 mmHg. Daily administration of Pitressin tannate to hypertensive rats allowed free access to water induced a similar decrease in BP as well as suppression of PRA. These results indicate that the hypotensive effect of water restriction in the two-kidney one-clip hypertensive rat model may be mediated, at least in part, through elevated circulating levels of vasopressin that subsequently inhibit renin release.

Antihypertensive and renal effects of cilazapril and their reversal by angiotensin in renovascular hypertensive rats

1988 ◽  
Vol 74 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Yu-An Ding ◽  
Shin-Tsu Chang ◽  
Shyh-Ming Shieh ◽  
Wann-Chu Huang
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Angiotensin Ii ◽  
Enzyme Inhibitor ◽  
Fractional Excretion ◽  
Hypotensive Effect ◽  
Hypertensive Rats ◽  
Renal Effects ◽  
Angiotensin Iii ◽  
Excretion Rates

1. The antihypertensive and renal effects of cilazapril, a new angiotensin converting enzyme inhibitor, were evaluated in both two-kidney, one-clip Goldblatt hypertensive rats (n = 11) and normotensive rats (n = 6). 2. Intravenous infusion of cilazapril (1 mg/kg followed by 25 μg min−1 kg−1) caused significant reductions of blood pressure from 163 ± 3 to 122 ± 4 mmHg and from 157 ± 2 to 113 ± 3 mmHg in two separate groups of hypertensive rats and from 124 ± 1 to 105 ± 2 mmHg in normotensive rats. The hypotensive effect in terms of absolute value or percentage change was greater in hypertensive rats than in normotensive rats (41 ± 6 vs 20 ± 3 mmHg or 25 ± 4% vs 16 ± 2%, respectively). 3. Cilazapril increased glomerular filtration rate, urine flow, and absolute and fractional excretion rates of sodium and potassium in the non-clipped kidney of hypertensive rats. In contrast, the clipped kidney exhibited a depressed renal function during cilazapril infusion. 4. In normotensive rats, the hypotensive and enhanced renal function responses to cilazapril were much less than those of the non-clipped kidney of hypertensive rats. 5. Superimposed administration of either angiotensin II or angiotensin III during cilazapril infusion completely reversed the blood pressure and bilateral renal responses of cilazapril in both hypertensive and normotensive rats. 6. These results indicate that cilazapril reduces arterial pressure and enhances renal excretion mainly via inhibition of angiotensin II and angiotensin III formation.

Influence of the sympathetic nervous system and vasopressin on the blood pressure lowering effect of nifedipine in deoxycorticosterone acetate–salt hypertensive rats

1987 ◽  
Vol 73 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Yutaka Takata ◽  
Yoshiaki Yamashita ◽  
Shuichi Takishita ◽  
Masatoshi Fujishima
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Calcium Influx ◽  
Hypotensive Effect ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Blood Pressure Lowering Effect ◽  
Hypotensive Action ◽  
Sympathetic Nervous

1. The role of the sympathetic nervous system and the effect of vasopressin (AVP) on the hypotensive action of nifedipine (Nf) were evaluated in conscious, unrestrained normotensive and DOCA–salt hypertensive rats. 2. The hypotensive response to Nf was much greater in DOCA rats than in the controls. 3. Solitary blockade of the sympathetic nervous system or AVP, did not alter the Nf effect in either DOCA or control rats. However, a combination clearly diminished the effect of Nf in the DOCA group, but enhanced it in the controls. The inhibition of angiotensin II (ANG II) augmented the hypotensive effect of Nf in control animals, but not in the DOCA rats. The percentage fall in blood pressure with Nf was much the same in both groups after the combined inhibition of the sympathetic nervous system and AVP. 4. The enhanced hypotensive action of Nf in DOCA rats may be dependent on the hyperactivity of the sympathetic nervous system and AVP, which facilitates calcium influx, and in the normotensive animals the depressor response to Nf may relate to blockade of the calcium influx, independent of the sympathetic nervous system, AVP and ANG II.

EFFECT OF THE EXPERIMENTAL DECIDUOMA ON STEROID HYPERTENSION IN THE RAT

1968 ◽  
Vol 58 (2) ◽  
pp. 177-182
Author(s):  
H. C. Moore ◽  
F. P. Biliczki
Keyword(s):  
Blood Pressure ◽  
Hypertensive Rats ◽  
Hypotensive Action ◽  
Equivalent Time ◽  
Metrial Gland ◽  
Decidual Reaction

ABSTRACT Experimental deciduomas which are maintained for 5 to 6 days do not lower the blood pressure in steroid hypertensive rats. In animals maintained longer only the metrial gland of the deciduoma survives but this too does not have a hypotensive action. It is concluded that the maternal decidual reaction in pregnant hypertensive rats is not responsible for the fall of blood pressure when this occurs at an equivalent time of gestation of up to 10 or 11 days and that the metrial gland is not responsible for the fall of blood pressure at whatever time the fall occurs during gestation.

scholarly journals Hypotensive Effect Induced by Mandibular Extension in Aged, Hypertensive Humans and Rats

2021 ◽  
pp. 1-5
Author(s):  
Cristina Del Seppia ◽  
Cristina Del Seppia ◽  
Giuseppe Federighi ◽  
Enza Fommei ◽  
Sergio Ghione ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Human Subjects ◽  
Mouth Opening ◽  
Hypotensive Effect ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Arterial Blood

Objectives: Previous research has shown that submaximal mouth opening by mandibular extension (ME) is followed by a prolonged reduction in blood pressure. This effect was observed in young and adult normotensive and hypertensive rats and in young normotensive human subjects. Methods: We assessed the effects of a ME for 10 minutes obtained with a fixed mouth opener in both hypertensive adult humans (aged 55 years or older) and elderly (6-7 months) anaesthetized, hypertensive rats (SHR). Blood pressure and heart rate were measured every 10 minutes by non-invasive automatic recorders for 30 minutes before and 120 minutes after the procedure. Nine human hypertensive subjects (7 experimental and 2 controls) and seven spontaneously hypertensive rats (5 experimental and 2 controls) were tested. Results: A statistically significant reduction in systolic blood pressure (SBP), mean arterial blood pressure (MABP) and heart rate (HR) was observed after ME in the seven hypertensive human subjects, in whom an average decrease of 15 mmHg for SBP, 10 mmHg for MABP and 7 bpm for HR, was observed. A similar hypotensive effect was recorded in spontaneously hypertensive rats that displayed a statistically significant decrease of SBP, DBP and MABP, amounting to about 40-50 mmHg. Conclusion: This study provides the first evidence that ME has an important and prolonged hypotensive effect when applied to subjects with high blood pressure, making their arterial blood pressure decrease toward normal values for at least two hours.

scholarly journals Antihypertensive Effect Of Magnesium Sulfate (Cormagnesin®) And Its Combination With Furosemide On Conscious Spontaneously Hypertensive Rats

2015 ◽  
Vol 8 (2) ◽  
pp. 112-117
Author(s):  
Katerina D. Simeonova ◽  
Krassimir D. Dimitrov ◽  
Nikolay D. Danchev
Keyword(s):  
Blood Pressure ◽  
Magnesium Sulfate ◽  
Spontaneously Hypertensive Rats ◽  
Antihypertensive Effect ◽  
Hypotensive Effect ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Significant Difference ◽  
Dose Dependent

SummaryThe present study demonstrates the antihypertensive effect of magnesium sulfate (Cormagnesin®) and its combination with Furosemide on conscious spontaneously hypertensive rats (SHR) after intravenous infusion. Experiments were carried out on six groups of conscious male SHR (n=6). Under short anesthesia the rats were chronically instrumented for intravenous (i.v.) drug administration. The arterial blood pressure (AP) was measured by indirect tale method. Cormagnesin®was applied by i.v. infusion in doses of 5, 20 and 40 mg/kg; and furosemide (10 mg/kg) was applied intraperitoneally. Experimental results showed significant decrease of AP after i.v. infusion of 20 mg/kg Cormagnesin®as well as after application of the Cormagnesin®and furosemide combination. The hypotensive effects of 40 mg/kg Cormagnesin®and of furosemide were not significant. There was no significant difference between the antihypertensive effects of Cormagnesin®and its combination with furosemide but the combination showed much better hypotensive effect than Furosemide (p<0.05). Our study demonstrated the antihypertensive effect of magnesium sulfate on conscious SHR after i.v. application. Our results suggest that the antihypertensive effect of magnesium sulfate in the doses applied is not dose-dependent. Magnesium sulfate potentiates the antihypertensive effect of furosemide in SHR.

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