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At least 19 recordsLinked to original sources
PubMed2000

Effects of aqueous extracts of Apocynum venetum leaves on spontaneously hypertensive, renal hypertensive and NaCl-fed-hypertensive rats.

Effects of aqueous extracts of Apocynum venetum leaves (Luobuma extracts) on the blood pressure were evaluated in hypertensive animal models, such as spontaneously hypertensive rats (SHR), renal hypertensive rats and NaCl-induced hypertensive rats. In SHR, administration of Luobuma (heat-processed and unprocessed leaves) extracts at a dose of 70 mg/rat per day significantly decreased the systolic blood pressure value, but their decreasing effects were weaker than that of captopril. The urine volume, and the urinary Na(+), K(+) and protein excretions were not significantly different between Luobuma-treated and untreated groups. In 3/4 nephrectomized rats, the Luobuma extracts significantly decreased the systolic blood pressure value, accompanied by significant increases of the urine volume and the urinary Na(+) and K(+) excretions. Furthermore, they decreased the blood urea nitrogen (BUN) level. In NaCl-induced hypertensive rats, the Luobuma extract decreased the systolic blood pressure value. However, it did not change the urinary excretions of Na(+), K(+) and protein. The BUN level was lower than that of control rats, but the serum total cholesterol (TC) level did not changed. From these findings, the Luobuma extracts have an anti-hypertensive effect, possibly due to amelioration of the kidney functions in the three experimental animal models.

Animals↗
PubMed1993

Spatial navigation learning in spontaneously hypertensive, renal hypertensive and normotensive Wistar rats.

The relation between blood pressure and cognitive performance was assessed in the spatial navigation task. Spatial learning by rats with spontaneous hypertension (SHR) and Goldblatt renal hypertension (RHR) was compared with that of normotensive Wistar rats (NR). The task required the rats to escape from water by finding a submerged and hidden platform. It was found that SHR rats showed improved learning capacity in the maze task in acquisition compared to the RHR and NR groups already on Day 1 and Day 2. The performances of all tested groups reached almost similar asymptotic level on Day 4 and in the probe trial on Day 5. After a reversal training the SHR rats did not show preference to swim in the new platform position quadrant. The present results confirm earlier reports on different behavioural characteristics associated with hypertension.

Animals↗
PubMed1987

Control of lumbar sympathetic nerve traffic by vagal cardiopulmonary baroreflexes in renal hypertension.

Renal nerve traffic is inhibited during volume expansion mainly because of stimulation of vagal cardiopulmonary baroreflexes. These responses are impaired in rabbits with renal hypertension caused by impaired cardiopulmonary baroreflexes. Previous studies have suggested that there may be differences in the extent to which renal hypertension alters reflex control of lumbar as compared with renal sympathetic nerve activity. The goals of this study were to determine if the responses to volume expansion of lumbar sympathetic nerve traffic also are impaired in renal hypertension and if this abnormality, if present, is caused by abnormalities in the vagal cardiopulmonary baroreflex. Experiments were done in alpha-chloralose-anesthetized normotensive (n = 9) and renal hypertensive (n = 7; 1 kidney, 1 wrap) rabbits. Infusion of dextran in saline raised arterial and left atrial pressures in both groups and decreased lumbar nerve traffic by -4.4 +/- 0.4% mm Hg rise in arterial pressure in the normotensive group and by -1.5 +/- 0.1% mm Hg in the hypertensive group (p less than 0.01). These responses were nearly abolished by sinoaortic denervation in both groups. These data indicate that the responses of lumbar nerve traffic to volume expansion are impaired in renal hypertension; this is mainly because of impaired arterial baroreflexes since vagal cardiopulmonary baroreceptors have minimal influence on lumbar nerve traffic, even in normotensive rabbits. These findings for the lumbar nerves are strikingly different from those reported previously for reflex control of the renal nerves in both normotensive and hypertensive rabbits.

Animals↗
PubMed1975

The clinical picture of renal hypertension.

Renal hypertension can usually be recognized only by examining all the features of the hypertensive illness. On the other hand, the investigation of a case of hypertension whose genesis was previously unclear can lead to the diagnosis of a hitherto unrecognized renal disease. The blood pressure values found in patients with renal hypertension are of widely differing degrees of severity. Slight rises in blood pressure (e.g. 140/90 mm Hg), can be a sign of renal disease in adolescent patients. 10-15% of the cases of chronic renal hypertension develop into malignant hypertension. High diastolic values above 120 mm Hg without renal symptomatology and without reduced renal function speak against a primary renal cause of the rise in blood pressure. The finding of hypertension developing during the course of renal disease is, with respect to the hypertensive cardiovascular complications, just as important as in the case of essential hypertension. Complications which can occur during renal hypertension include cardiac insufficiency, hypertensive encephalopathy, retinopathy, hypertensive crises and acceleration of the renal disease.

Acute Disease↗
PubMed1996

Enhanced cholinergic activity in the medulla oblongata of DOCA-salt hypertensive and renal hypertensive rats.

We previously demonstrated that cholinergic activity in the medulla oblongata is enhanced in adult spontaneously hypertensive rats (SHR), a genetically hypertensive rat model. In this study, we examined possible alterations of medulla oblongata cholinergic mechanisms in nongenetic forms of hypertension, using deoxycorticosterone acetate (DOCA)-salt hypertensive and renal hypertensive rats. At a fully developed stage of hypertension in DOCA-salt hypertensive and renal hypertensive rats, choline acetyl-transferase (CAT) activity in the rostro-ventral medulla oblongata was enhanced, whereas there was no change in the activity of CAT in other parts of the medulla oblongata. There was no alteration of the medulla CAT activity in prehypertensive SHR or at an early stage of renal hypertension. Increases in blood pressure and plasma catecholamine levels induced by physostigmine (0.5 mg/kg, i.p.) were enhanced in DOCA-salt hypertensive and renal hypertensive rats. These findings suggest that cholinergic activities in the medulla oblongata are enhanced and that such activities are involved in enhancement of the sympathetic nervous system in non-genetically hypertensive rats. It seems unlikely that the altered cholinergic activity in the rostral ventrolateral medulla of adult SHR occurs genetically.

Animals↗
PubMed1979

Laboratory tests in the evaluation of renal hypertension.

Renal hypertension is better understood now as a result of the development of new laboratory techniques which permit the identification of the surgically curable forms of renovascular and renal parenchymal hypertension. The rationale for and efficacy of these new advances are discussed and a practical approach to the diagnosis of renal hypertension is offered.

Angiotensin II↗
PubMed1982

A comparison of antihypertensive effects of atenolol and propranolol in the spontaneously hypertensive, DOCA/saline hypertensive and renal hypertensive rats.

Antihypertensive effects of a long-term oral regimen of atenolol were studied in SHR, DOCA/saline hypertensive and renal hypertensive rats (one kidney, one clip) in comparison with the effects of propranolol. Both the beta-blockers prevented the development of hypertension in SHR but did not affect that in DOCA/saline and renal hypertensive rats. Both of the beta-blockers produced no acute hypotensive effects on the established DOCA/saline and renal hypertension of the rat, although they produced a decrease in the heart rate.

Animals↗
PubMed1999

[Study on the relationship between plasma endothelin nitric oxide concentration and renal hypertension and renal function].

OBJECTIVE: To investigate the relationship between plasma endothelin(ET), nitric oxide(NO) levels and, renal hypertension and renal function. METHODS: The plasma concentration of ET-1 was detected by immunofluorescence assay. The plasma concentration of NO was detected by biochemistry assay. RESULTS: 1. In renal disease patients, plasma concentration ET-1 was markedly elevated, and plasma concentration of NO was decreased, compared with the healthy subjects(P < 0.01). 2. Plasma concentration of ET-1 was markedly increased and plasma concentration of NO was decreased in the patients with renal hypertension. 3. Plasma level of ET-1 was higher, and plasma level of NO was lower in the patients with renal function damage than that of those without renal function damage. 4. BP, BUN and Scr were positively correlated with plasma ET-1, but they were negatively correlated with plasma concentration of NO. CONCLUSION: Plasma ET-1 and NO may play an important role in pathogenesis of renal hypertension; the change of their levels may be related to the progress of these renal diseases.

Adult↗
PubMed1979

Reactivity of gomerular afferent and efferent arterioles in renal hypertension.

Renal tissue from neonatal hamsters was grafted into the cheek pouch of adult hamsters. Renal hypertension was induced in 28 hamsters, and sham operation was performed in 27. When blood pressure became elevated in hypertensive hamsters (10 to 12 days), the renal microcirculation of both groups was evaluated by direct microscopy. Wall and luminal diameter and vascular responses to norepinephrine (NE) and angiotensin II (AII) were determined on glomerular afferent and efferent arterioles and on the corresponding cheek pouch arterioles. In the hypertensive hamsters, the luminal diameter of the afferent arteriole increased, as did the wall/lumen ratio of the efferent arteriole. Although all vessels responded to direct application of NE and AII in both groups, the response of the afferent to AII and the response of the efferent to both NE and AII was greater in the hypertensive hamsters as compared to the sham-operated hamsters. These results indicate that during the development of renal hypertension structural alterations of glomerular vessels and the selective vascular responses to vasoactive agents would lead to an increased glomerular capillary pressure.

Angiotensin II↗
PubMed1976

Mechanism of renal hypertension.

Renal hypertension of the two-kidney type is divided into three stages. In the first, hypertension results from the vasoconstrictor effect of angiotensin II. This persists to some extent in the second phase but there is in addition a slow-developing pressor effect, also resulting from angiotensin II and probably attributable to sodium. In the first two phases removal of the abnormal kidney corrects the hypertension. This fails in the third phase because changes in the opposite kidney maintain hypertension. Renin and angiotensin are probably not involved at this stage.

Angiotensin II↗
PubMed1986

Elastase, collagenase, and cathepsin D activities in the aortas of spontaneously hypertensive and renal hypertensive rats.

In an attempt to clarify the roles of proteases in the developmental mechanisms of hypertensive vascular lesions, changes in activities of aortic elastase, collagenase, and cathepsin D in spontaneously hypertensive rats (SHR) and renal hypertensive rats were biochemically investigated. In SHR, elastase activity initially showed a significant increase, once two-fold higher than that in the control; but the activity tended to decrease earlier than that in the control. In both SHR and normotensive control rats collagenase activities tended to increase with advancing age. The activity in SHR was two-fold higher than that in the control at all ages examined. In both younger SHR and normotensive rats cathepsin D activities proved to be increased with advancing age, while in old rats the activities tended to decrease. The activity in SHR was three- to fivefold higher than that in the control at all ages examined. In renal hypertensive rats, the activities of elastase, collagenase, and cathepsin D increased gradually with increasing blood pressure, at levels significantly higher than those in the control. These findings suggest that the metabolisms of proteins such as elastin and collagen, expressed by these enzyme activities, are accelerated under hypertensive conditions.

Aging↗