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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serial hemodynamic studies have become increasingly important in hypertension research. These studies have been accomplished using the A-V shunt. The progressive decline in the number of A-V shunts in favor of the A-V fistula has limited the number of measure cardiac output, the intra-arterial blood pressure cannot be measured through it. The present paper describes a technique for measuring both the cardiac output and direct intra-arterial blood pressure using the bovine artegraft.
Nephron 1975
PMID:Measurement of intra-arterial blood pressure and cardiac output through the bovine artegraft. Hemodynamic measurements through the bovine artegraft. 112 51

Noradrenaline and alpha-methylnoradrenaline applied to the area of the nucleus tractus solitarii of the medulla oblongata decreased arterial blood pressure and heart rate of anesthetized normotensive rats. Alpha-Methylnoradrenaline was more effective than noradrenaline. Prior administration of the alpha-adrenergic blocking agent phentolamine at the same site prevented the central inhibitory action of the two catecholamines and even reversed the effect on blood pressure. The hypotensive responses evoked by electrical stimulation or alpha-methylnoradrenaline application were found to have a common distribution of the most effective site, comprising the middle-caudal part of the nucleus tractus solitarii at the obex level. Bilateral electrolytic lesions of this area caused an immediate and severe hypertension. The data suggest that the area of the nucleus tractus solitarii is a site of action of hypotensive drugs which may act by noradrenergic receptor stimulation in the brain. In addition brain serotonin may also play an inhibitory role as indicated by the association of elevated blood pressure and brainstem serotonin depletion during treatment with para-chorophenylalanine of normotensive and genetic hypertensive rats.
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PMID:Role of noradrenaline and serotonin in the central control of blood pressure in normotensive and spontaneously hypertensive rats. 114 22

The responses of blood pressure, plasma renin activity (PRA) and plasma aldosterone concentration (PAC) to infusion of either angiotensin II (10 ng/Kg/min) or norepinephrine (100 ng/Kg/min) were observed in 25 patients with essential hypertension. The difference in modes of response between low renin essential hypertension and normal or high renin essential hypertension was analyzed. For comparison, 5 patients with Conn's syndrome, 4 with renovascular hypertension, and 5 normotensive subjects were also studied. Following infusion of antiotensin II the changes in diastolic blood pressure (DBP) were +24+/-3.0 mmHg in low renin essential hypertension and +25+/-3.1 mmHg in normal or high renin essential hypertension in PRA -0.28+/-0.06 ng/ml/h in low renin essential hypertension and -0.69+/-0.02 mg/ml/h in order and in PAC +3.7+/-1.4 and +7.6+/-1.8 ng/100 ml respectively. There was a significant difference in magnitude of response in PRA between the 2 groups of essential hypertension (p less than 0.05). Norepinephrine induced rise in DBP with decreases both in PRA and PAC. The mean changes in DPB were +6+/-1.4 mmHg in low renin essential hypertension and +16+/-2.2 mmHg in another and the pressor response in the later was significantly greater (p less than 0.01). The changes in PRA were -0.14+/-0.07 ng/ml/h in low renin essential hypertension and -0.67+/-0.26 ng/ml/h in normal or high renin essential hypertension, and in PAC -4.9+/-1.3 and -3.3+/-1.9 ng/100 ml respectively. The greater fall in PRA in normal or high renin essential hypertension was observed but the difference between the 2 groups of essential hypertension was not significant. The changes in PAC did not parallel the changes in PRA. Angiotensin II indcued essentially similar effects on blood pressure in both groups but the greater feedback inhibition of PRA was produced by this peptide in normal or high renin essential hypertension than in low renin essential hypertension. Norepinephrine induced significantly greater pressor effect in normal or high renin essential hypertension. The adopted dose of norepinephrine suppressed both PRA and PAC and a tendency to the greater fall in PRA was observed in normal or high renin essential hypertension. There was no difference in responses of PAC to both agents between the 2 groups of essential hypertension.
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PMID:Effect of pressor agents on blood pressure, plasma renin activity and plasma aldosterone concentration in essential hypertension. 115 95

Deoxycorticosterone pivalate (2.5 mg/kg) given intramuscularly on four occasions 10-15 days apart over a period of 45 days to unilaterally nephrectomized adult male mongrel dogs, receiving as drinking solution 0.9% NaCl in 5% dextrose, resulted in an average sustained rise in the mean arterial blood pressure of 30 mm Hg (1 mm Hg - 133 N/m2) in 60% of the animals. Hypertensive dogs had in their arterial tissues generally more sodium, potassium, magnesium, and calcium than the similarly treated but non-hypertensive dogs, but compared to the tissues of operated untreated or unoperated normotensive dogs, only sodium and calcium were significantly higher. The dogs who were similarly treated but did not develop hypertension had in their arterial tissues less sodium, potassium, and magnesium than operated untreated or unoperated normotensive dogs. Norepinephrine content in the branches of mesenteric arteries of all deoxycorticosterone- and NaCl-treated animals, irrespective of their blood pressure, was significantly lower, and in the myocardium significantly higher, than either the unoperated normotensive or operated but not further treated dogs. It is concluded, therefore, that in deoxycorticosterone + NaCl treatment the dogs which developed hypertension had more arterial sodium, potassium, magnesium, and calcium than those who were similarly treated but remained within the limits of normal blood pressure, and that there was no difference between hypertensive and non-hypertensive dogs in regard to their cardiovascular norepinephrine content.
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PMID:Water, cations, and norepinephrine content of cardiovascular tissues of unilaterally nephrectomized dogs treated with deoxycorticosterone and NaCl. 120 92

The authors examined the changes in arterial blood pressure and the content of Noradrenaline in the myocardium, brain and aorta of rats with hypertension due to nephrectomy and treatment with desoxycorticosterone and NaCl, and after a chronic 6-month treatment of hypertension with various antihypertensive means. The most significant reduction of noradrenaline in the three of the examined tissues was found in rats, which received dic. sulfyram (100 mg/kg per os). Clondine (10 mkg/kg, per os) manifested the strongest hypotensive effect and lowered the level of noradrenaline in the myocardium, while it was raised in the aorta. Reserpine (10 mkg/kg, s. c) induced a clear reduction of Noradrenaline content in the brain, but an increase in the other two tissues. Insignificant hypotensive effect was observed in animals, treated with guanetidine (0.5 mg/kg, per os), which did not affect substantially noradrenaline in the examined organs. The increase of noradrenaline level was established in the three of the organs of animals, treated with alpha-methyl-DOFA (25 mg/kg, per os). Furosemide (1 mg/kg, s.c.) induced a statistically significant elevation of noradrenaline in the aorta, but was noneffective to noradrenaline in the myocardium and brain.
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PMID:[The effect of prolonged treatment of hypertensive rats with antihypertensive drugs of various actions on the arterial tension and noradrenaline level in the myocardium, brain and aortal]. 121 18

The influence of postural changes on renal function was determined in 13 patients with nephroptosis and in 5 normal subjects by measuring GFR in the erect and supine positions. The result indicate that GFR was reduced in the erect position in 10 of 13 patients with either unilateral or bilateral nephroptosis whereas GFR was increased in the erect position in 4 of 5 patients without renal disease. One patient with bilateral nephroptosis and renovascular hypertension was studied before and after surgical correction of his disease. The observations indicate that patients with nephroptosis may have significant reductions in renal function when they assume an upright position, and suggest that GFR measurements in the supine and erect position in patients with nephroptosis can be helpful in evaluating this disease.
Nephron 1976
PMID:Influence of postural changes on the glomerular filtration rate in nephroptosis. 124 74

A study has been made to assess the incidence of hypertension in patients who have suffered an episode of renal trauma sufficiently severe to cause haematuria. Sixty-three patients were studied and 63 age- and sex-matched controls were also studied. At follow-up, 6-138 months after injury, 13 of the patients who had suffered renal trauma and 12 of the control subjects had a diastolic blood pressure above 99 mm Hg. Three patients showed significant reduction in the size and volume of the previously damaged kidney. In this group, renal trauma did not appear to be associated with an increased risk of permanent hypertension.
Nephron 1976
PMID:Renal trauma and persistent hypertension. 124 75

Norepinephrine concentration and dopamine-beta-hydroxylase activity were measured in the plasma of 10 dysautonomic patients and 10 normal subjects while they were reclining, standing and exercising. While reclining, dysautonomic patients had normal norepinephrine concentrations and blood pressure, but after standing they did not have a normal increase in their levels of norepinephrine (P less than 0.005), dopamine-beta-hydroxylase (P less than 0.05) or plasma protein concentration (P less than 0.01); they became hypotensive. In reclining dysautonomic patients there appeared to be a correlation between blood pressure and plasma norepinephrine concentration. These data support the view that hypertension and hypotension in dysautonomia are related to the rate of norepinephrine release.
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PMID:Deficient sympathetic nervous response in familial dysautonomia. 124 55

Noradrenaline releases prostaglandins in the kidney, and in rats these augment rather than reduce vasoconstriction produced by the amine. Homogenates of kidneys of New Zealand rats inbred for hypertension exhibit lower prostaglandin inactivation by 15-hydroxydehydrogenase than controls. At the same time, augmentation of noradrenaline vasoconstriction by the released prostaglandin is exaggerated. This biochemical defect could be the inherited abnormality primarily responsible for the development of hypertension in these animals.
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PMID:Genetic hypertension in rats is accompanied by a defect in renal prostaglandin catabolism. 126 20

Selective partial occlusion of the intrarenal arteriolar bed with microspheres in rats resulted in contracted kidneys simulating those of benign nephrosclerosis in man. There was no elevation of blood pressure, renal vein plasma measured by radioimmunoassay, or juxtaglomerular indices of affected kidneys. It is unlikely that arteriolar lesions are pathogenetically related to the development of hypertension.
Nephron 1976
PMID:Renal arteriolar obstruction without hypertension. 126 15


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