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.

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.

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.

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.

Did Ground Cover Change Over Geologic Time?

2000 ◽  
Vol 6 ◽  
pp. 171-182 ◽  
Author(s):  
Ben A. LePage ◽  
Hermann W. Pfefferkorn
Keyword(s):  
Fossil Record ◽  
Ground Cover ◽  
The Other ◽  
Detailed Account ◽  
Geologic Time ◽  
The Past ◽  
Other Hand ◽  
Plant Fossil

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).

Effect of chronic NG-nitro-L-arginine methyl ester (L-NAME) on blood pressure and renal function in conscious uninephrectomized spontaneously hypertensive rats

1998 ◽  
Vol 76 (1) ◽  
pp. 63-67 ◽  
Author(s):  
María Reverte ◽  
Olga Flores ◽  
Belén Gallego ◽  
Antonio Lestón ◽  
José Miguel López-Novoa
Keyword(s):  
Blood Pressure ◽  
Drinking Water ◽  
Renal Function ◽  
Methyl Ester ◽  
Spontaneously Hypertensive Rats ◽  
Low Dose ◽  
Potassium Excretion ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Sodium And Potassium

We have studied during 30 days the effect of a low dose of NG-nitro-L-arginine methyl ester (1 mg ·kg-1 ·day-1 in drinking water) in the presence of D- or L-arginine (1 mg ·kg-1 ·day-1 in drinking water) in comparison with D- or L-arginine alone on blood pressure and renal function in conscious uninephrectomized female spontaneously hypertensive rats. At the end of the study, there was a significant increase in systolic blood pressure in the NG-nitro-L-arginine methyl ester + D-arginine group (307 ± 6 mmHg (1 mmHg = 133.3 Pa), n = 14, p << 0.05) in comparison with NG-nitro-L-arginine methyl ester + L-arginine (281 ± 6 mmHg, n = 14), L-arginine (262 ± 5 mmHg, n = 13), and D-arginine (258 ± 7 mmHg, n = 12) groups. There were no changes in diuresis, proteinuria, or sodium and potassium excretion between differently treated animals during this study. These results suggest that in uninephrectomized female spontaneously hypertensive rats, after 1 month blockade of NO synthesis with a low dose of NG-nitro-L-arginine methyl ester, vasculature is under tonic control by NO and it is not correlated with renal dysfunction.Key words: Key words: NG -nitro-L-arginine methyl ester (L-NAME), kidney, hypertension, spontaneously hypertensive rats, renaldysfunction, uninephrectomy.

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.

Renin content and excretory function of the kidney in rats with experimental hypertension

1962 ◽  
Vol 202 (4) ◽  
pp. 795-799 ◽  
Author(s):  
H. Brunner ◽  
P. A. Desaulles ◽  
D. Regoli ◽  
F. Gross
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Renal Hypertension ◽  
Experimental Hypertension ◽  
Elevated Blood ◽  
Hypertensive Rats ◽  
Excretory Function ◽  
Contralateral Kidney ◽  
Ligation Of The Ureter ◽  
Renin Content

To determine relationship between kidney renin content and excretory function, rats with renal hypertension induced by unilateral clamping of the renal artery were given an oral load of 3 ml of 0.9% saline/100 g body wt. Excretion of the saline load was accelerated in rats with renal hypertension as well as in animals with hypertension due to overdosage with cortexone and salt, provided that the loading experiment was made 3–4 weeks after hypertension was established, but not when animals had been hypertensive for 11–14 weeks. Renin concentration was markedly reduced in the unclamped kidney and also in the kidney of the rats overdosed with cortexone and salt. Excreting capacity of the clamped kidney was compared with that of the unclamped kidney, after removal or after functional elimination of the contralateral kidney, by ligation of the ureter, 3, 24, and 48 hr after the operation. In all experiments excretion of saline load by the unclamped kidney was more rapid than by the clamped kidney, but the highest values were reached in the presence of a functional clamped kidney. Only in rats with elevated blood pressure was the load more rapidly excreted than in normal rats, but hypertension alone cannot be the only factor responsible, the excretion not being accelerated in unilaterally nephrectomized hypertensive rats. Although these hint at a connection between the renin concentration and renal function the nature of this relationship remains uncertain.

II.—On upright Equisetites Stems in the Oolitic Sandstone in Yorkshire

1913 ◽  
Vol 10 (1) ◽  
pp. 3-7 ◽  
Author(s):  
T. G. Halle
Keyword(s):  
Lower Surface ◽  
Upright Position ◽  
The Other ◽  
Mineral Matter ◽  
Vertical Position ◽  
Other Hand ◽  
Mode Of Occurrence ◽  
Coal Measures

Stems of Ecquisetites columnaris (Brong.) have long been known to occur in a vertical position in the sandstones of the Inferior Oolite on the Yorkshire coast. This mode of occurrence has commonly been held as proving that the stems are preserved in the position in which they once grew, having been buried in situ beneath the layers of sand that accumulated on the spot. On the other hand, it has been argued that the upright position need not be primary; it might be as readily explained if the stems are regarded as drifted and secondarily deposited on the spots where they are now found. It is well known and has been pointed out, particularly in the discussions of the upright stems in the Coal-measures, that a drifting tree often has a tendency to sink in a vertical position, the root-end being heavier because of adhering mineral matter or from some other reason. Phillips describes, in his Geology of the Yorkshire Coast, a locality at High Whitby where upright stems of Equisetites columnaris occur in the sandstone. He continues: “They … are broken off or imperfect above, and seldom reach to the upper surface of the bed; they are also broken off below, but commonly pass to the lower surface; and some of the lower joints nearest the roots are found in the subjacent bed of shale.”

High-potassium diet attenuates salt-induced acceleration of hypertension in SHR

1991 ◽  
Vol 260 (1) ◽  
pp. R21-R26 ◽  
Author(s):  
Y. Sato ◽  
K. Ando ◽  
E. Ogata ◽  
T. Fujita
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
High Potassium ◽  
Spontaneously Hypertensive ◽  
Antihypertensive Action ◽  
High K ◽  
Wistar Kyoto ◽  
Renal Vascular

We studied the effects of K supplementation (8% KCl) for 4 wk on blood pressure (BP), Na space, and renal hemodynamics in 5-wk-old, spontaneously hypertensive rats (SHR) or age-matched Wistar-Kyoto rats (WKY) eating normal-NaCl (0.66%) or high-NaCl (8%) diet. In WKY, high-Na and/or high-K diets had no effects on BP. In SHR, Na load accelerated the development of hypertension, whereas K supplementation did not affect BP of normal-Na SHR but attenuated the increase in BP with Na load. Correspondingly, Na load in SHR significantly increased renal vascular resistance (RVR), and K supplementation attenuated the increased RVR of Na-loaded SHR. Moreover, Na space of SHR was increased compared with that of WKY, and although Na load did not affect Na space, K supplementation tended to decrease Na space in SHR. These results indicate that 9-wk-old SHR is relatively volume-expanded compared with age-matched WKY, and K supplementation could improve the lowered slope of the pressure-Na excretion relationship in SHR, resulting in maintenance of Na balance. Thus the data suggest that changes in RVR, which might be intimately related to renal function for Na excretion, contribute to both salt sensitivity of SHR and antihypertensive action of K supplementation in Na-loaded SHR.

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