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

Interrelations between age and plasma renin, aldosterone and cortisol levels, urinary catecholamiens, plasma and blood volumes, exchangeable body sodium and blood pressure wwere studied in 28 young (19 to 29 years), 16 middle-aged (32 to 58 years) and 15 elderly (60 to 74 years) healthy subjects. Supine and upright plasma renin and supine aldosterone levels decreased while urinary noradrenaline excretion rate increased progressively with aging (r= greater than 0.34; p less than 0.05), with significant differences in mean values between young and elderly subjects (p less than 0.02). There was also an age-related decrease in upright plasma aldosterone concentration, although this was no statistically significant. Furthermore, mean plasma cortisol concentrations increased in response to upright posture in elderly ( + 50%; p less than 0.02), but not in young ( --10%) or middle-aged ( --8%) subjects. Blood pressure correlated with age ( r =0.35; p less than 0.05) or noradrenaline excretion rate ( r= 0.34) in the entire study population and with blood volume in the elderly ( r = 0.68), but not in the young or middle-aged study. Groups. There were no significant age-related differences in the body sodium/volume state, basal plasma cortisol levels or urinary adrenaline excretion rate, and plasma renin or aldosterone levels did not correlate with these parameters or with blood pressure. It is concluded that the influence of age on plasma renin or aldosterone levels, plasma cortisol responsiveness to upright posture, and urinary noradrenaline excretion should be taken into consideration, whenever these factors have to be interpreted in patients with arterial hypertension or other clinical disorders. Further more, these data are conssitent with the possiblity that in normal man increases in supine blood pressure with aging may be related at least partly to concomitant changes in free peripheral noradrenaline.
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PMID:Interrelations between age and plasma renin, aldosterone and cortisol, urinary catecholamines, and the body sodium/volume state in normal man. 89 8

We report a 14-year-old boy with severe hypertension who was cured by surgical removal of a pheochromocytoma. The tumor was shown biochemically and morphologically to secrete predominantly noradrenaline. The metabolic effects noted in this patient were raised free fatty acid levels and depressed insulin levels, hyperreninemia, hypercalcemia, and hypercalciuria with normal parathyroid function. All these abnormalities returned to normal after removal of the tumor. It is suggested that these effects were mediated via beta-adrenergic stimulation of the excess noradrenaline.
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PMID:The metabolic effects of excess noradrenaline secretion from a pheochromocytoma. 90 78

1 Plasma noradrenaline concentrations were similar in rats following unilateral renal arterial constriction (two kidney Goldblatt model) and in sham-operated control rats. 2 The development of hypertension was not affected by pretreatment with intracisternal injections of 6-hydroxydopamine. 3 These data suggest that sympathetic mechanisms do not contribute to the development of hypertension in this model.
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PMID:Central and peripheral noradrenaline in the two kidney model of renovascular hypertension in the rat. 92 50

Plasma concentrations of noradrenaline (NA), adrenaline (A) and renin (R) were measured in 29 regular haemodialysis patients (RHP) [13 normotensive, 10 hypertensive, 6 binephrectomised] and in 15 healthy control subjects (C) under various physiological conditions: supine-standing-walking. RHP had significant higher plasma levels of noradrenaline and adrenaline in the mean than C. All RHP responded to passive orthostasis with a significant increase in diastolic blood pressure, heart rate and plasma NA. In contrast to C, plasma NA did not drop after two hours of active orthostasis. Hypertensive RHP had significant higher plasma concentrations of R and A than normotensives. It is concluded that the sympathetic nervous system (SNS) plays a minor role in hypertensive blood pressure regulation of RHP. The adequate response to passive orthostasis in RHP with regard to diastolic blood pressure, heart rate and plasma NA indicates and intact function of the SNS under this condition. Hypertension in RHP not controllable by salt and volume depletion can be attributed to elevated levels of R, which in turn may stimulate adrenaline release from the adrenals. The mechanisms responsible for the elevated levels of circulating catecholamines remain unclear: an inhibition of re-uptake, disturbances in enzymatic metabolism or/and abolished renal clearance are suggested.
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PMID:Plasma noradrenaline levels in regular haemodialysis patients. 93 19

The effect of hypertensive plasma on the responses of an isolated artery preparation to noradrenaline were studied. In addition, because of the association between hypercholesterolaemia and hypertension, the effect of pure cholesterol and low density lipoprotein on the arterial responses to noradrenaline was also investigated. Both hypertensive plasma and low density lipoprotein potentiated the responses of the arterial preparation to noradrenaline.
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PMID:Effects of hypertensive plasma on the responses of an isolated artery preparation to noradrenaline. 93 93

Turnover of noradrenaline (NA) and dopamine (DA) in some regions of the rat brain was determined after 1 and 3 weeks of daily injections of lysine vasopressin (LVP) and 2 weeks after the termination of 28-day LVP injections. Disappearance of 3H-DA was estimated in the hemispheres, brain stem and striatum and of 3H-NA in the hemispheres and brain stem after intraventricular injection of 3H-tyrosine. A significant acceleration of 3H-NA disappearance from the hemispheres was found in all the experimental animals and from the brain stem 3 weeks after LVP adminstration and 2 weeks after its withdrawal. No marked changes in dopamine turnover in the examined regions of the rat brain were found. Since prolonged vasopressin administration produces hypertension in the rat it seems likely that central NA, but not DA, plays a role in the vasopressin-induced hypertension.
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PMID:Turnover of catecholamines in some regions of the rat brain during prolonged vasopressin administration and after its withdrawal. 94 87

The urinary excretion of free noradrenaline (NA), adrenaline (A), dopamine (DA), the DA/NA ratio in the urine, plasma renin activity (PRA) and their mutual relationship were investigated in 71 patients suffering from different types of arterial hypertension. In spite of the fact that the mean values of excreted catecholamines, with the exception of pheochromocytoma, lie within the range of values found in healthy controls, certain differences were found in spectrum of excreted catecholamines. In patients with labile, malignant and renovascular hypertension and in pheochromcytoma the higher mean excretion of NA and the low DA/NA ratio was accompanied by the higher PRA in comparison with fixed benign essential hypertension. On the other hand, in hypertension with low PRA (essential hypertension with suppressed renin and Conn's syndrome) a low excretion of NA and high DA/NA ratio was found. There was a significant, if not even very close negative correlation between the PRA and DA/NA ratios both in recumbent and upright position. The rise of PRA on standing up was followed by an increased excretion of NA while the excretion of DA did not change or decreased. Hence the DA/NA ratio when standing up showed a decreasing tendency as compared with values when lying down. Application of the beta-blocker Inderal decreased the PRA and the blood pressure not only in juvenile hypertensive patients with hyperkinetic circulation but also in the early phases of renovascular hypertension. It thus appears that endogenous catecholamines, first of all the ratio between the renin-inhibiting DA and the renin-stimulating NA, participate as one of several factors in the regulation of secretion and of the plasma levels of renin not only in juvenile hypertensive patients with hyperkinetic circulation but also in other types of hypertension.
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PMID:Relationship between plasma renin activity and urinary catecholamines in various types of hypertension. 97 8

One hundred and forty-four human pineal glands obtained at necropsy were analysed for their content of catecholamines, indolealkylamines and calcium and the findings related to sex, age, terminal illness and medication. A preliminary study of 45 pineal organs revealed no significant differences in amine pattern in glands removed 6-48 hours post mortem. A statistically significant difference of pineal weight, calcium and amine content could not be detected in glands of age-matched groups of male and female patients who died suddenly without apparent clinical illness. A highly significant correlation between pineal weight and calcium content was established in patients older than 60 years. Considerable variability of amine levels existed in all groups of patients. Adrenaline as well as noradrenaline were detected in most glands. This finding was corroborated by the formation of radioactively labelled adrenaline from noradrenaline and 14C-S-adenosylmethionine by extracts from human pineals. Dopamine was most abundant in glands from patients dying of malignant tumours. The content of the indolealkylamines (5-hydroxytryptamine and melatonine) varied between a few nanograms to 21 mug/g tissue. The highest mean calcium content was detected in glands of patients who died of renal disease associated with hypertension.
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PMID:Catecholamine, indolealkylamine and calcium levels of human pineal glands in various clinical conditions. 100 48

In the unanaesthetized rat morphine caused increased dopamine (DA) turnover, unchanged or possibly increased central noradrenaline (NA) turnover (utilization), hypertension and tachycardia. In the anaesthetized rat, brain DA turnover was not affected, whereas the NA-turnover was decelerated, particularly in some brain regions, e.g. cerebral cortex and medulla oblongata, and hypotension and bradycardia was obtained. Both biochemical and cardiovascular effects of morphine were antagonized by naloxone. A very small dose of morphine (1 mg/kg) caused tachycardia also in the anaesthetized rat. Decerebration just inferior to the inferior colliculus abolished the conscious rat, but left the circulatory, depressant actions of the drug unchanged. The morphine-induced cardiovascular effects, particularly the hypotension and bradycardia in the anaesthetized animal, are suggested to be related to, or mediated by, the effects of the drug on brain NA-mechanisms, especially in view of several similarities between morphine and the antihypertensive alpha-adrenergic agonist clonidine. Whereas higher brain structures appear important in the excitatory, circulatory effects of morphine, structures below the decerebration level, e.g. medulla oblongata, appear primarily involved in the hypotension and bradycardia obtained in the anaesthetized animal. Possibly, morphine has a diphasic dose-response curve with respect to cardiovascular function and, by inference, on brain noradrenergic mechanisms.
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PMID:Effects of morphine on central catecholamine turnover, blood pressure and heart rate in the rat. 101 34

Interrelations between blood pressure, circulatory volume, plasma renin activity (PRA) and urinary catecholamine excretion rates were studied in normal subjects and patients with benign essential hypertension. Mean plasma or blood volumes related to lean body mass, products of blood volume and the logarithm of PRA, and catecholamine excretion rates did not differ significantly as between normal and hypertensive subjects. In both normal subjects and hypertensive patients, blood pressure correlated positively with noradrenaline excretion rate (r = 0.40 and 0.36 respectively; p less than 0.025), but not with adrenaline excretion, circulatory volume or the volume-renin product. The logarithm of PRA correlated inversely with mean blood pressure in normal subjects (r = -0.40; p less than 0.001), but not in hypertensive patients; however, there was no convincing evidence of an inappropriate blood pressure-PRA relationship as a prominent feature in the hypertensive patients. PRA did not correlate with blood volume. Patients with low PRA relative to sodium excretion (21% of hypertensive population) were consistently normovolemic, but tended to be older and excreted less (p less than 0.025) adrenaline than normal or high-PRA patients. The patient subgroup with high PRA relative to sodium excretion (11% of population) was hypovolemic (p less than 0.02); despite this, urinary sodium output was high (172 +/- 64 meq/24 hr). These data reveal no evidence for major roles of PRA, circulatory volume and free peripheral catecholamines in the maintenance of benign essential hypertension. Low-PRA essential hypertension is usually not a hypervolemic state, but may reflect diminished adrenergic activity, factors associated with aging and effects of a high systemic pressure. High PRA in benign essential hypertension may be at least partly a consequence of hypovolemia resulting from high blood pressure-induced sodium diuresis.
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PMID:[Correlations between blood pressure, blood volume, plasma renin and urinary catecholamines in normal subjects and in patients with benign essential hypertension]. 101 97


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