Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Present knowledge of the mechanisms regulating release of renin is reviewed with particular emphasis on neural factors. Evidence is given for a direct effect of renal innervation on beta adrenergic receptors in juxtaglomerular cells, and for the involvement of reflex release of renin in conditions such as tilting and acute salt depletion. Participation of neural and nonneural mechanisms of control is also shown to occur in other conditions, such as aortic constriction and hemorrhage. The view is held that neural sympathetic factors might explain some of the renin disturbances found in essential hypertension. First, in patients with high renin hypertension part of the hypertension is renin-dependent, and these pressor levels of renin seem to be neurally induced since they can commonly be suppressed by beta adrenoreceptor blocking agents. Second, the hypothesis is presented that patients with low renin hypertension, at least those who have no volume disturbance, have a blunted sympathetic control of renin release. Therefore a sufficiently precise test of sympathetic activity, and possibly of body fluid volumes, should be associated with renin profiles for a better understanding of the pathophysiology of arterial hypertension and as a better guide to therapeutic management. Indeed, most of the available antihypertensive drugs act on sympathetic activity, body fluid volume or renin, and this multifaceted profile would provide more rational guidelines for treatment.
 ...
PMID:Control of renin release: a review of experimental evidence and clinical implications. 0 64

Primary aldosteronism and renovascular hypertension are two different diseases in which renin determinations are necessary for establishment of diagnosis or therapeutic procedure. Low renin values which are not stimulated by acute stimuli combined with elevated plasma aldosterone concentrations confirm the diagnosis of primary aldosteronism. When in a patient with proven renal artery stenosis a significant difference in renal venous renin activity is observed between the two kidneys, a connection between hypertension and renal artery stenosis is likely when in addition the renin secretion of the unaffected kidney is suppressed. A favourable outcome for surgery can be predicted when the individual clinical picture in such a case is also considered. A similar view also holds for the connection between hypertension and unilateral small kidney not due to renal artery stenosis. In essential hypertension the plasma renin level makes it possible to a certain extent to predict whether a patient will benefit from diuretics or from beta-blocking agents. Despite this experience, however, renin determinations are not indicated in every case of essential hypertension. It has not been proven that the prognosis of this disease is improved by renin oriented monotherapy rather than by effective treatment with other antihypertensive agents.
 ...
PMID:[The value of renin determination in the diagnosis of hypertension]. 0 81

The past 10 years have firmly established the role of beta-adrenoceptor blocking agents in the treatment of hypertension. They have been shown to lower systolic and diastolic blood pressure in the lying and standing position in mild, moderate and severe hypertension. Precise indications for beta-blockade have not yet been completely defined. Some authorities regard them as the drug of first choice in the management of most grades of idiopathic hypertension. There are in addition certain situations where beta-blockade seems especially suitable. These include the presence of associated coronary heart disease manifest either as angina pectoris or dysrhythmia. These agents can be introduced when side effects from other drugs are severe or intolerable and are valuable in the management of hypertensive young males since beta-blocking drugs do not interfere with sexual function. Compared with normotensive subjects 'stress' has been shown to produce excessive rise of blood pressure in those with labile or sustained idiopathic hypertension. After therapy with beta-blocking agents the rise in blood pressure after 'stress' is reduced. If labile and/or mild hypertension are the precursors of subsequently more severe sustained hypertension, then long term beta-blockade may help to control this response.
 ...
PMID:Indications for beta-adrenoceptor blocking drugs in hypertension. 0 35

Eleven beta-adrenergic receptor blocking agents and derivatives were evaluated for their ability to affect systolic arterial blood pressure and pulse rate in unanesthetized, male spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto (WKY) controls. Animals ranged from 7 to 76 weeks of age. The subcutaneous injection of 5 and 45 mg/kg metoprolol in 52 to 64 week old SHRs and 45 mg/kg twice a day to 26 to 29 week old SHRs produced a significant decrease in blooc pressure. The subcutaneous injection of pindolol (0.1 and 1.0 mg/kg) produced a greater and more consistent depressor effect in mature SHRs. The subcutaneous administration of sotalol (100 mg/kg) and alprenolol (20 mg/kg) resulted in a depressor action which was significant 120 minutes after injection of the drug. In the doses used, propranolol, oxprenolol, 4-hydroxypropranolol and K9-1366 produced pressor effect in SHRs. Propranolol did not cause this pressor effect in prehypertensive (seven week old) SHRs. Practolol, dextro-propranolol and KO-1313 had no effect on blood pressure in the doses used. Propranolol, pindolol, metoprolol, dextro-propranolol, 4-hydroxypropranolol, practolol, oxprenolol, KO-1366 and KO-1313 produced no significant effects on blood pressure in normotensive WKY controls in the doses tested. Placing oral doses of 160 mg/kg/day of metoprolol in the drinking water for seven days significantly lowered blood pressure in 14 week old SHRs previously exposed to ineffective doses of 77 mg/kg/day for 24 days. The administration of oral doses of oxprenolol (40 mg/kg/day) in drinking water for three weeks had a slight but insignificant pressor effect. Smaller doses of metoprolol (15 and 39 mg/kg/day for three to four weeks) and practolol (70 to 85 mg/kg/day for two weeks) had no effect on 52 week old SHRs. Oral doses of pindolol, metoprolol, practolol and oxprenolol had no significant effect on blood pressure in WKY controls. There was no clear relationship between the effects of the drugs on blood pressure and their ability to affect the pulse rate. Similarly, there did not appear to be any consistent relationship between the potency of the beta-blocking drug and the blood pressure lowering action. In addition, neither cardioselective beta-blockade nor sympathomimetic properties allowed the prediction of blood pressure responses to the administration of those agents possessing these features. Although SHRs provide a valuable model of human essential hypertension, the variable effects reported here and elsewhere in the literature require caution as to the applicability and usefulness of testing and evaluating beta-adrenergic blocking drugs for theri potential anti-hypertensive effects in this particular form of experimental hypertension.
 ...
PMID:Beta-adrenergic receptor blocking drugs in spontaneous hypertension. 1 Jul 29

Patients with essential hypertension can be subdivided into groups with low (19%), normal (59%) or high (23%) renin sodium index. The proportion with low renin hypertension increases with age. Patients with high renin fall in two categories: younger patients with fairly mild hypertension and older patients with more severe hypertension and signs of renal disease. The antihypertensive efficacy of betablocker monotherapy is best in high renin forms, good but less consistent in normal renin patients and uniformly bad in low renin hypertensives. In relation to age, betablockers normalized blood pressure (less than or equal to 95 mm Hg diastolic) in three-quarters of the younger-than-40-year-olds, in about half of those 40-60 years of age but in only 20% of those over 60 years. On this basis, it is postulated that the older patients with a low renin exhibit a relatively hypoadrenergic state whereas those with a normal or high renin--for a given age and elevated pressure--have a relatively increased adrenergic nervous activity. Because the betablockers have a potent suppressive action on the renin-angiotensin system--and, as a consequence, on angiotensin vasoconstriction, aldosterone volume expansion and central stimulatory feedback mechanisms--their antihypertensive mode of action may be linked to an important extent, although not exclusively, to renin suppression.
 ...
PMID:Renin and age as determinants of a predominantly betablocker-based antihypertensive drug program. 1 85

From analyses of the effectiveness of beta-blocker monotherapy in relation to the patient's age and to pre-treatment renin determinations an antihypertensive drug program is proposed in which beta-blockers form the cornerstone. Patients with essential hypertension can be subdivided into groups with low (19%), normal (59%), or high (23%) renin sodium index. The proportion with low renin hypertension increases with age. Patients with high renin fall into two categories: younger patients with fairly mild hypertension and older pateients with more severe hypertension and signs of renal disease. The antihypertensive efficacy of beta-blocker monotherapy is best in high renin forms, good but less consistent in normal renin patients and uniformly bad in low renin hypertensives. In relation to age, beta-blockers normalized blood pressure (larger than or equal to 95 mmHg diastolic) in three-quarters of the younger than 40-year-olds, in about half of those aged 40--60 years, but in only 20% of those aged over 60 years. On this basis, it is postulated that the older patients with a low renin exhibit a relatively hypoadrenergic state while those with a normal or high renin--for a given age and elevated pressure--have a relatively increased adrenergic nervous activity. Because the beta-blockers have a potent suppressive action on the renin-angiotensin system--and, as a consequence, on angiotensin vasoconstriction, aldosterone volume expansion and central stimulatory feedback mechanisms--their antihypertensive mode of action may be linked to an important extent, though not exclusively, to renin suppression.
 ...
PMID:A beta-blocker-based antihypertensive drug program guided by age and renin. 1 22

Studies using a sensitive radioenzymatic assay for plasma noradrenaline suggest there is a selective overactivity of the sympathetic nervous system in essential hypertension. Methodology which allows the study of local sympathetic turnover in CNS nuclei and peripheral blood vessels is described. This approach has been used to study the non-innervated sympathetic turnover phaeochromocytoma. It is suggested that studies of local regulatory mechanism in neurotransmitter release are required to give a greater understanding of the central and peripheral role of the sympathetic nervous system in the pathogenesis of hypertension.
 ...
PMID:Studies of neurotransmitter release in the pathogenesis of hypertension. 1

Several experimental observations accumulated during recent years have suggested an active participation of the sympathetic system in the pathogenesis and maintenance of hypertension in various experimental models of hypertension. The evaluation of sympathetic tone by various indirect means in human hypertension has also revealed that the sympathetic system plays an important role in the maintenance of hypertension in a subgroup of the human hypertensive population. The study of circulating catecholamines, which appears to be the best and most reliable indirect means to evaluate the sympathetic activity in the human, at present, has indicated that 25 to 40 per cent of patients with essential hypertension are characterized by higher basal circulating catecholamines and by a higher sympathetic reactivity in response to postural changes. These hyperadrenergic patients are also characterized by a higher heart rate, heart contractility, cardiac index and probably by higher plasma renin activity. The identification of these patients as a separate entity is desirable since it is possible that the evolution of the hypertensive disease and the response to therapy differ in this group of patients. The study of these patients could lead to a better understanding of the mechanisms underlying the pathogenesis of cardiovascular complications and to the development of more rational and efficient therapeutic approaches.
 ...
PMID:The sympathetic system in hypertension. 2 13

1. In seventeen patients with untreated essential hypertension the sodium and water contents of leucocytes were significantly increased, whereas the rate constant for ouabain-sensitive sodium efflux was significantly reduced. 2. These abnormalities were not found in fourteen other patients with well-controlled hypertension. 3. Preliminary observations in accelerated hypertension suggest a different pattern of abnormality in leucocyte sodium metabolism.
 ...
PMID:Abnormal sodium transport in leucocytes from patients with essential hypertension and the effect of treatment. 2 75

1. The antihypertensive effect of a new beta-adrenoceptor blocking agent, trimepranol (10--14 mg/twice daily), chlorthalidone (50 mg every second day) and their combination was studied in eighteen patients with mild to moderate essential hypertension. In a controlled randomized cross-over study the drugs were given for 6 week periods. 2. A significant and equal decrease in blood pressure was achieved both with trimepranol and chlorthalidone, whereas their combination was significantly more effective. 3. Trimepranol significantly antagonized the chlorthalidone-induced hypokalemia. 4. The results favor the use of diuretic or diuretic-beta-adrenoceptor blocker combination over beta-adrenoceptor blocker monotherapy in the treatment of mild to moderate hypertension.
 ...
PMID:Effect of diuretic, beta-adrenoceptor blocking agent and their combination on elevated blood pressure and serum potassium: a cross-over study. 2 53


1 2 3 4 5 6 7 8 9 10 Next >>