Calcium antagonists preferentially dilate preglomerular vessels of hydronephrotic kidney

The hydronephrotic kidney of Inactin-anesthetized female Wistar rats was exteriorized in a controlled bath to directly observe preglomerular and postglomerular vessels via television microscopy. Nitrendipine, added to the bath in a concentration that did not alter blood pressure, induced a concentration-dependent dilation of preglomerular vessels. The arcuate artery maximally dilated by 29 +/- 4%, the interlobular artery by 24 +/- 5%, the afferent arteriole near the interlobular artery by 60 +/- 9%, and near the glomerulus by 28 +/- 13%. In contrast the efferent arteriole near the glomerulus dilated by only 11 +/- 6% and near the welling point by 7 +/- 9%. Similarly, diltiazem significantly dilated preglomerular vessels but not efferent arterioles. Acetylcholine significantly dilated all preglomerular vessels and dilated the afferent arterioles near the glomerulus (by 51 +/- 8%) to a greater extent than the calcium blockers. Acetylcholine also significantly dilated the efferent arterioles (near the glomerulus by 26 +/- 5% and near the welling point by 12 +/- 3%). These data suggest that the tone of the preglomerular vessels of the hydronephrotic kidney is more dependent on the entry of extracellular calcium through calcium antagonist-sensitive channels (i.e., potential dependent) than is the tone of the afferent arterioles near the glomerulus and the efferent arterioles.

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The Influence of Neonatal Treatment with Guanethidine on the Development of Isolation-Induced Hypertension in Adult Rats

Clinical Science ◽

10.1042/cs0650469 ◽

1983 ◽

Vol 65 (5) ◽

pp. 469-474 ◽

Cited By ~ 2

Author(s):

S. M. Gardiner ◽

T. Bennett

Keyword(s):

Blood Pressure ◽

Nervous System ◽

Sympathetic Nervous System ◽

Wistar Rats ◽

Adult Rats ◽

Male And Female ◽

Neonatal Treatment ◽

Induced Hypertension ◽

Female Wistar Rats ◽

Sympathetic Nervous

1. Rats housed individually in glass metabolism cages develop hypertension. Since previous experiments have provided some evidence for the involvement of the sympathetic nervous system in the maintenance of the hypertension, the present work was designed to explore the possible involvement of the sympathetic nervous system in the genesis of isolation-induced hypertension. 2. Male and female Wistar rats were treated neonatally with guanethidine, with a protocol designed to produce an extensive peripheral sympathectomy; control rats received saline. 3. The effects of isolation on systolic blood pressure and fluid and electrolyte balances were studied when the rats were mature. 4. Guanethidine-treated rats did not develop hypertension in response to isolation whereas control rats did. 5. There were no significant differences between the fluid and electrolyte balances of the guanethidine-treated rats compared with controls throughout the period of isolation. 6. It is concluded that a fully functional sympathetic nervous system is required for the development of isolation-induced hypertension, but its involvement is not through a modulation of renal function.

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Influence of endothelium-derived relaxing factor on renal microvessels and pressure-dependent vasodilation

AJP Renal Physiology ◽

10.1152/ajprenal.1993.265.2.f285 ◽

1993 ◽

Vol 265 (2) ◽

pp. F285-F292 ◽

Cited By ~ 15

Author(s):

J. Hoffend ◽

A. Cavarape ◽

K. Endlich ◽

M. Steinhausen

Keyword(s):

Blood Flow ◽

Renal Perfusion ◽

Local Administration ◽

Relaxing Factor ◽

Female Wistar Rats ◽

Stepwise Reduction ◽

Afferent Arterioles ◽

Endothelium Derived Relaxing Factor ◽

Hydronephrotic Kidney

The influence of endothelium-derived relaxing factor (EDRF) on renal microvessels and autoregulation was visualized in vivo, in the split hydronephrotic kidney of rats. EDRF synthesis was inhibited by local administration of 10(-5) M NG-nitro-L-arginine methyl ester (L-NAME). Diameters of arcuate arteries decreased by 17%. In cortical vessels efferent arterioles constricted more (13-16%) than interlobular arteries and afferent arterioles (7-12%). Cortical glomerular blood flow (GBF) decreased by 46% after L-NAME. A similar behavior of blood flow and vascular diameters was also observed in juxtamedullary (JM) arterioles. The responses to acetylcholine but not to sodium nitroprusside were attenuated after L-NAME. After local administration of L-arginine (10(-3) M) diameters of all vessels and GBF increased, vascular responses to L-NAME were blunted. Stepwise reduction of renal perfusion pressure revealed that autoregulation was preserved in cortical vessels after L-NAME. In JM arterioles, which do not autoregulate in female Wistar rats, autoregulation of GBF was enhanced after L-NAME. These data suggest that tonic formation of EDRF influences basal renal hemodynamics to a considerable extent. EDRF may also impair autoregulation of JM glomeruli without disturbing autoregulation of cortical glomeruli.

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Direct evidence that thromboxane mimetic U44069 preferentially constricts the afferent arteriole.

Journal of the American Society of Nephrology ◽

10.1681/asn.v8125 ◽

1997 ◽

Vol 8 (1) ◽

pp. 25-31

Author(s):

K Hayashi ◽

R Loutzenhiser ◽

M Epstein

Keyword(s):

Calcium Antagonist ◽

Direct Evidence ◽

Rat Kidney ◽

Afferent Arteriole ◽

Filtration Fraction ◽

Perfused Rat Kidney ◽

Txa2 Receptor ◽

Txa2 Receptor Antagonist ◽

Vasodilator Action ◽

Hydronephrotic Kidney

The thromboxane A2 (TXA2) mimetic U44069 has been demonstrated to reduce the GFR and filtration fraction of the normal isolated perfused rat kidney markedly, suggesting a predominant constriction of preglomerular vessels. To assess this possibility directly, effects of U44069 on the renal microvessels of the isolated perfused hydronephrotic kidney were examined. At 10(-6) mol/L, U44069 elicited a 27 +/- 2% decrease in afferent arteriolar (AA) diameter (from 18.8 +/- 0.3 to 13.7 +/- 0.3 micron, P < 0.001). In contrast, efferent arteriolar (EA) diameter decreased by only 9 +/- 1% (from 16.4 +/- 0.5 to 15.0 +/- 0.5 micron, P < 0.001). These effects on both AA and EA were completely reversed by the TXA2 receptor antagonist SQ29548. The calcium antagonist diltiazem reversed U44069-induced AA constriction by 83 +/- 5%. The U44069-induced EA constriction was insensitive to the vasodilator action of diltiazem at concentrations from 10(-8) to 10(-6) mol/L, but at 10(-5) mol/L, diltiazem increased the EA diameter significantly, albeit modestly. Nifedipine also reversed the U44069-induced AA constriction (81 +/- 7%), but failed to inhibit the EA constriction at concentrations from 10(-9) to 10(-6) mol/L. These findings constitute the first direct evidence that a TXA2 agonist preferentially constricts the afferent arteriole. Furthermore, the ability of both the calcium antagonist and SQ29548 to reverse the renal microvascular actions of TXA2 agonists suggests a potential utility of these agents in ameliorating TXA2-induced renal hemodynamic abnormalities.

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Abstract 220: Exercise Training Attenuates Hypertension and Insulin Resistance in Old Fructose-fed Ovariectomized Rats

Hypertension ◽

10.1161/hyp.62.suppl_1.a220 ◽

2013 ◽

Vol 62 (suppl_1) ◽

Author(s):

Jacqueline F Machi ◽

Nathalia Bernardes ◽

Daniele S Dias ◽

Ivana C Moraes-Silva ◽

Fernando Dos Santos ◽

...

Keyword(s):

Insulin Resistance ◽

Blood Pressure ◽

Adipose Tissue ◽

Exercise Training ◽

Wistar Rats ◽

Physical Capacity ◽

Ovariectomized Rats ◽

Ovarian Hormone ◽

Female Wistar Rats ◽

Hormone Deprivation

Menopause and aging are associated with a gradual increase in systolic blood pressure. Poor eating habits through food containing fructose, have also been related to alterations in the cardiovascular system; however, there are few studies available in the literature relating exercise training (ET), menopause, aging and metabolic syndrome. The aim of the present study was to investigate the effects of ET in ovarian hormone deprivation and/or fructose consumption in old Wistar rats. Female Wistar rats (24 months old) were ovariectomized, fed with fructose (100g/L in drinking water) or normal water, and submitted to an ET protocol in treadmill (1 h/day; 5 days/wk for 8 wk, ~ 40-60% of maximum test) or kept sedentary. The groups were: ovariectomized (O, n= 8), ovariectomized trained (OT, n= 8), ovariectomized fructose (OF, n= 8) and ovariectomized fructose trained (OFT, n= 8). Glycemia, triglycerides, adipose tissue, insulin resistance, physical capacity and blood pressure (BP) were evaluated at the end of the protocol. While the glycemia values remained within the normal range (O:90.1±7.; OT:85.2±2; OF:86±2; OFT:80.6±3 mg/dl) and the triglycerides values were increased in OF group (OF:182±20 vs. O:140.3±9; OT:143.5±7;; OFT:140 ±12 mg/dl). The physical capacity was increased in both OFT (1.8±0.1 Km/h) and OF (1.6±0.07 Km/h) when compared with sedentary peers (O:1.1±0.05; OF: 1.1±0.05 Km/h). The metabolic results showed that ET decreased the adipose tissue in (OT: 6.7±0.9 and OFT: 5.28±0.6 vs. OF: 10.07±0.6 g), and insulin resistance (OT:4.8±0.2 and OFT: 5.0±0.2 vs. OF: 3.2±0.6 mg/dl/%). No differences were observed in O group (O: 6.5±0.8g and 4.5±0.2 mg/dl/min). Finally, ET attenuated the increase in mean BP in both OT and OFT rats (O:119±2; OT 110±2; OF:119±2; OFT: 107±1 mmHg). The same behavior was observed in systolic BP (O:142±2; OT 127±2; OF:143±2; OFT: 129±1 mmHg) and diastolic BP (O:100±2; OT 92±2; OF:98±2; OFT: 89±1 mmHg). In conclusion, low to moderate aerobic ET can attenuate the deleterious effects of ovarian hormone deprivation, and/or fructose consumption, especially the blood pressure increase in old female Wistar rats.

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Sex-specific Effects of Spironolactone on Blood Pressure in Gonadectomized Male and Female Wistar Rats

Hormone and Metabolic Research ◽

10.1055/s-0031-1299774 ◽

2012 ◽

Vol 44 (04) ◽

pp. 291-295 ◽

Cited By ~ 8

Author(s):

M. Michaelis ◽

P. Hofmann ◽

F. Götz ◽

C. Bartel ◽

T. Kienitz ◽

...

Keyword(s):

Blood Pressure ◽

Wistar Rats ◽

Male And Female ◽

Specific Effects ◽

Female Wistar Rats

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Effects of atrial natriuretic peptide on renal arterioles: morphometric analysis using microvascular casts

AJP Renal Physiology ◽

10.1152/ajprenal.1990.259.6.f936 ◽

1990 ◽

Vol 259 (6) ◽

pp. F936-F944 ◽

Cited By ~ 2

Author(s):

K. Kimura ◽

Y. Hirata ◽

S. Nanba ◽

A. Tojo ◽

H. Matsuoka ◽

...

Keyword(s):

Atrial Natriuretic Peptide ◽

Natriuretic Peptide ◽

Urinary Sodium Excretion ◽

Afferent Arteriole ◽

Efferent Arteriole ◽

Vascular Casts ◽

Normal Rat ◽

Afferent Arterioles ◽

Rat Kidneys ◽

Atrial Natriuretic

In normal rat kidneys, the effect of atrial natriuretic peptide (ANP) on the diameter of the arterioles was evaluated by scanning electron microscopy of vascular casts. Acryl resin was infused into rat kidneys during the administration of ANP, either alone or with norepinephrine (NE). ANP infusion constricted the proximal efferent arteriole in the superficial cortex. Although NE constricted the proximal and distal segments of the afferent arteriole in the superficial cortex, the addition of ANP reversed the constriction and further constricted the efferent arteriole. In the deep cortex, only the proximal segment of the afferent arteriole was dilated by ANP when infused with NE. In a separate set of experiments, ANP increased both the glomerular filtration rate (GFR) and urinary sodium excretion (UNaV), and NE decreased the renal blood flow (RBF). However, administration of ANP after NE recovered RBF and increased GFR as well as UNaV. Results indicate that ANP increases GFR and natriuresis by constricting the efferent arteriole. NE appears to decrease RBF by constricting the afferent arteriole. ANP antagonizes the renal effects of NE primarily by dilating afferent arterioles.

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An experimental study to see the antihypertensive effects of gymnema sylvestre and acorus calamus in wistar rats and its comparison with amlodipine

Asian Journal of Medical Sciences ◽

10.3126/ajms.v8i3.16778 ◽

2017 ◽

Vol 8 (3) ◽

pp. 11-15

Author(s):

Dheeraj Kumar Singh ◽

Narendra Kumar ◽

Anjula Sachan ◽

Preet Lakhani ◽

Sachin Tutu ◽

...

Keyword(s):

Blood Pressure ◽

Systolic Blood Pressure ◽

Wistar Rats ◽

Oral Feeding ◽

Acorus Calamus ◽

Gymnema Sylvestre ◽

Traditional System ◽

Female Wistar Rats ◽

Prevalence Of Obesity ◽

The Individual

Background: The prevalence of obesity is increasing worldwide. Obesity has a direct correlation with insulin resistance and various cardiovascular diseases like hypertension,dyslipidaemia etc. Hypertension is considered as a major independent risk factor for coronary disease and stroke for all age, race & sex groups. Gymnema sylvestre and Acorus calamus are two well known herbs of traditional system of medicine effective in various diseases.Aims and Objectives: The present study was designed to explore the antihypertensive effects of Gymnema sylvestre (GS) and Acorus calamus (AC), individually as well as in combination, in wistar rats.Materials and Methods: Female wistar rats, weighing between 150- 200 g, were included in the study. They were divided into eight groups with six rats in each group. High Fat diet (HFD) was used to induce hypertension in all the groups except group 1 which was fed with normal rodent diet. Drugs were given to the rats by oral feeding cannula.Results: Feeding rats with HFD for 4 weeks lead to signifi cant increase in the mean systolic blood pressure. Both Gymnema sylvestre and Acorus calamus signifi cantly reduced the systolic blood pressure. Combination of both these (Gymnema sylvestre 200mg/kg and Acorus calamus 200mg/kg) as well as Gymnema sylvestre (200mg/kg) individually has an effect comparable to Amlodipine. Individual drugs had no signifi cant effect on heart rate while the combination of these two drugs signifi cantly reduced the heart rate.Conclusions: The present study concludes that extracts of Gymnema sylvestre and Acorus calamus has a signifi cant antihypertensive action in rodent model of hypertension. Combination is found superior to the individual drugs.Asian Journal of Medical Sciences Vol.8(3) 2017 11-15

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INFLUENCE OF PEPTIDE IMITATING α-SPIRAL OF B ERYTHROPOETHIN ON THE DEVELOPMENT OF MORPHOFUNCTIONAL DISORDERS IN EXPERIMENTAL PRECLAMPPS

Journal of Volgograd State Medical University ◽

10.19163/1994-9480-2020-2(74)-53-56 ◽

2020 ◽

Vol 74 (2) ◽

pp. 53-56

Author(s):

I.V. Golubev ◽

◽

M.A. Zatolokina ◽

V.V. Gureev ◽

A.V. Polyanskaya ◽

...

Keyword(s):

Blood Pressure ◽

Wistar Rats ◽

New Drugs ◽

Pathological Changes ◽

Functional Tests ◽

Treatment And Prevention ◽

Urgent Task ◽

Morphological Picture ◽

Female Wistar Rats ◽

Α Helix

Preeclampsia remains a formidable disease in the second half of pregnancy. Therefore, the search for new drugs for the treatment and prevention of preeclampsia is an urgent task of modern pharmacology. Materials and methods. The experiment was performed on female Wistar rats. The studied drugs were administered from 10 to 21 days of pregnancy. Functional tests were performed on the 21st day of pregnancy. Results. The use of a peptide that imitates erythropoietin α-helix B in experimental preeclampsia leads to a pronounced correction of pathological changes: blood pressure decreased, microcirculation in the placenta increased, and the morphological picture in the placenta improved. Resume. The results indicate the promise of the use of a peptide imitating α-helix B erythropoietin in experimental preeclampsia.

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Effect of verapamil on myocardial changes in experimental hypertensive rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161643 ◽

1990 ◽

Vol 48 (3) ◽

pp. 816-817

Author(s):

Selma Yilmazer ◽

Ismail Seçkin ◽

Mustafa Tasyürekli ◽

Oktay Arda ◽

Güngör Satiroglu

Keyword(s):

Electron Microscopy ◽

Blood Pressure ◽

Wistar Rats ◽

Control Group ◽

Hypertensive Rats ◽

Group Iii ◽

Group I ◽

Treatment Of Hypertension ◽

Female Wistar Rats ◽

Control Group Group

Recent experimental and clinical studies have reported on the effectiveness of calcium antagonists in the treatment of hypertension. The influence of such therapy on the morphologic features of heart, however has not been systematically studied. In the present study we have investigated the effect of verapamil, a calcium antagonist, on blood pressure and on ultrastructural features of myocardium in rats made hypertensive with DOCA + salt.Experiments were carried out with 24 female Wistar rats, 4 weeks of age. The animals were divided into 3, 8 animals per group. Group I was considered as the control group. Group II was injected intraperitoneally with 3 mg/kg daily of DOCA for 5 weeks and 154 NaCl was added in their drinking water. Group III received 8mg/kg daily of verapamil hydrochloride (Isoptin, Knoll Pharmaceutical Co.) orally, in additon to DOCA and salt. Five weeks after the start of the experiment systolic blood pressure was recorded and animals were killed. Left ventricle was dissected and prepared for electron microscopy.

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