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

Moderate pyridoxine deficiency in adult male Sprague-Dawley rats results in significant hypertension, associated with a general sympathetic stimulation, including an increase in the turnover of norepinephrine in the heart. Treatment of these rats with pyridoxine reversed blood pressure to normal within 24 h. Treatment of pyridoxine-deficient rats with clonidine or alpha-methyl dihydroxyphenylalanine (alpha-methyl DOPA) also reduced the blood pressure of these animals to normal. There was also a significant increase in the Bmax of high and low affinity [3H]p-amino-clonidine binding to crude synaptosomal membrane preparations of the brain stem of deficient rats indicating chronic underexposure of alpha 2 adrenoreceptors to endogenous norepinephrine.
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PMID:Alterations in brainstem alpha 2 adrenoreceptor activity in pyridoxine-deficient rat model of hypertension. 215 1

Abana is a herbomineral medicinal preparation with a property of down-regulation of beta-adrenergic receptors. A double-blind, parallel group study was conducted in 43 Indian men and women suffering from hypertension to evaluate the antihypertensive effect of Abana and compare it with that of methyldopa (M-DOPA). Twenty-one patients received 800 mg tds of Abana and 22 patients received 250 mg tds of M-DOPA for 4 weeks. Blood pressure and pulse rate were recorded at weekly intervals. Relevant clinical and biochemical investigations were carried out before and after treatment. In patients treated with Abana, there was a significant fall both in systolic B.P. (from 167 +/- 3.73 to 145 +/- 6.11 mmHg) and in diastolic B.P. (from 110 +/- 1.86 to 91 +/- 3.04 mmHg) at the end of 4 weeks. Similarly in patients treated with M-DOPA, systolic blood pressure was significantly reduced from 165 +/- 4.92 to 146 +/- 4.9 mmHg and diastolic blood pressure was reduced from 106 +/- 2.74 to 96 +/- 2.67 mmHg after 4 weeks. The onset of antihypertensive effect was earlier and there was a higher percentage of responders (80%) in the Abana-treated group. None of the patients had clinically or biochemically significant side-effects. The results of this study suggest that therapy with Abana proved highly effective in hypertensive patients.
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PMID:Double blind comparative trial of Abana and methyldopa for monotherapy of hypertension in Indian patients. 219 99

A long-lasting decrease of the basal and stress-induced arterial blood pressure was obtained in rats with inherited emotional stress-induced hypertension by means of injections of the dopamine precursor L-DOPA during early postnatal ontogeny (21-25 days of the life). "Permanent" hypotensive effect of L-DOPA was caused by the elevation of the brain but not peripheral catecholamine levels and was not related to a stimulation of the hypothalamic-pituitary-adrenocortical system in response to administration of the dopamine precursor. The restoring effect of L-DOPA was produced through enhancement of synthesis of the brain noradrenaline and, perhaps, adrenaline. The effect was associated with a normalization of the response of the brain adrenergic system to noradrenaline.
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PMID:Correction of arterial blood pressure in adult rats with inherited stress-induced arterial hypertension by enhancement of catecholamine metabolism in early postnatal period. 236 63

Several studies have shown that the development of high blood pressure in spontaneously hypertensive rats (SHR) can be attenuated by feeding them modified fat diets. In the present study, eight weeks after treatment with eicosapentaenoic acid (EPA; 100 mg/kg/day s.c.) SHR had lower systolic blood pressure (BP); (tail-cuff plethysmography) compared to saline-injected SHR: 180.0 +/- 2 vs. 204.0 +/- 1 mmHg, respectively, (p less than 0.001). There was no significant difference in the BP of EPA and saline-treated WKY (Wistar-Kyoto) rats. Heart rate (HR) decreased with age in both the SHR and WKY rats and no significant effect of EPA was observed in WKY rats; the decrease in heart rate in the SHR group was significantly diminished. EPA did not significantly alter growth rate of SHR and WKY rats. However, aged-matched WKY rats weighed more than the SHR. The pressor responses to norepinephrine in doses of 0.3 and 3.0 microgram/kg, i.v., as well as plasma NE, DOPA and MHPG, were also not significantly affected by EPA-supplementation in both SHR and WKY rats. Data from the present study support the view that EPA might be an effective treatment of hypertension that develops via mechanisms unrelated to sympathetic activity or vascular reactivity to adrenergic neurotransmitters.
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PMID:Acute and chronic effects of eicosapentaenoic acid (EPA) on the cardiovascular system. 255 5

A long-lasting decrease of the basal and stress-induced arterial blood pressure was obtained in rats with inherited emotional stress-induced arterial hypertension by means of injections of the dopamine precursor L-DOPA during early development (21-25 days after birth). The restoring effect of L-DOPA was produced through enhancement of synthesis of the brain noradrenaline and, perhaps, adrenaline. The effect was associated with a normalization of the response of the brain adrenergic system to noradrenaline and, presumably, with increase of tyrosine hydroxylase activity in the cortex and hindbrain.
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PMID:Persistent hypotensive effect of L-dopa given early during development to rats with inherited stress-induced arterial hypertension. 256 97

A 62-year-old male, was admitted on Oct. 7, 1987 because of productive cough and dyspnea. He worked for an iron factory, where pneumoconiosis was regarded as an occupational disease, for 40 years. No abnormal finding had been noted on his mass screening chest roentgenograms. He was well until three years ago when hypertension and Parkinsonism were noted. Since then he was treated with beta blockers, L-DOPA, amantadine and bromocriptine. Two weeks before admission, he suddenly complained of dyspnea and productive cough. His chest roentgenograms showed diffuse reticulonodular infiltration in both lung fields. The partial pressure of oxygen of the arterial blood was 65.9 Torr. The first transbronchial lung biopsy obtained from right B8 on Sept. 29, 1987 (before the admission) revealed some epithelioid granulomas and the second biopsy obtained from right B10 on Oct. 14, 1987 demonstrated bronchiolar edema and infiltration of inflammatory cells. Fibrotic changes associated with carbon dust between airways and vessels were also noted. Lymphocyte stimulation index by bromocriptine was 362%, and that by amantadine, 139%, L-DOPA, 150%, respectively. After ceasing the administration of bromocriptine, productive cough, dyspnea and the reticulonodular shadows diminished gradually. These findings strongly suggest that the interstitial pulmonary lesions are bromocriptine-induced interstitial pneumonitis. His occupational exposure to inorganic dust may be a predisposing factor.
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PMID:[A case of bromocriptine-induced interstitial pneumonitis in an iron factory worker exposed to sand dust]. 261 76

Turnover rates, as estimated from the accumulation of the intermediates, 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) following decarboxylase inhibition, were used to investigate the relationship between central catecholaminergic and serotonergic neurons and the development of hypertension in the one-kidney, one-clip renal hypertensive rats. Results indicated that at one week following clipping, 5-HTP accumulation was decreased in the posterior hypothalamus. At 5 weeks no changes were observed. At 20 weeks higher accumulations of both DOPA and 5-HTP were observed in the medulla oblongata while in the anterior hypothalamus DOPA accumulation was increased.
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PMID:Turnover of central biogenic amines in one-kidney, one-clip renal hypertensive rats. 310 60

Kidneys form dopamine (DA) from L-dopa and serotonin from L-5-hydroxytryptophan (L-5-HTP) via aromatic L-amino acid decarboxylase. We compared the ability of isolated perfused kidneys from adult (20-week-old) spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) to form these biogenic amines. Renal vascular resistance (RVR) was greater in perfused kidneys from SHR (n = 10) than WKY (n = 8) (p less than 0.01). Slight decreases in RVR were observed during L-dopa infusion but these were unrelated to DA formation. L-Dopa infusion was associated with greater DA output in SHR than WKY in both the renal venous and urinary effluents although the latter did not achieve statistical significance. L-5-HTP increased RVR to a greater degree in SHR than WKY kidneys. This was associated with larger quantities of serotonin in the urinary and venous effluents and greater pressor responses to exogenous serotonin in SHR than WKY kidneys; however, either parameter alone was not significantly increased. Our findings do not support a deficiency of intrarenal DA formation as a pathogenic factor for hypertension in SHR. Biogenic amine formation is as great if not greater in SHR than WKY kidneys and appears to contribute largely to the greater increases in renal resistance seen in SHR kidneys on infusion of L-5-HTP. Enhanced renal serotonin formation may elevate blood pressure, whereas enhanced renal DA formation would favor blood pressure lowering, perhaps as a compensatory mechanism.
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PMID:Formation of biogenic amines by isolated kidneys of spontaneously hypertensive rats. 348 34

In a newly developed rat strain with inherited stress-sensitive arterial hypertension (ISSAH) an attempt was made to reduce arterial blood pressure by L-DOPA injections during a short time period of the early ontogenesis. It was shown that L-DOPA injections to rats on days 7-9 or 14-16 of life had no effect. The same procedure performed on 21-23 or 21-25-day-old rats was followed by a decrease in the basal and stress-induced arterial blood pressure levels, measured in adulthood. Injections of dopamine-beta-hydroxylase inhibitor (FLA-59) with parallel L-DOPA administration completely blocked the blood pressure decreasing effect. It can be suggested that injections of L-DOPA in the 4th week of post-natal life reduce the blood pressure level in ISSAH rats by enhancing the rate of brain noradrenaline biosynthesis.
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PMID:[Correction of arterial pressure in rats with hereditary hypertension by altering catecholamine metabolism in early ontogeny]. 367 71

Synthesis of dopamine (DA) was studied in cortical slices of Sprague-Dawley (SD) rat kidneys incubated with L-DOPA (10(-6) M). In morphological studies, formaldehyde-induced histofluorescent deposits were detected at the apical pole of the convoluted parts of the proximal tubules. Elsewhere along the nephron, no positive reaction appeared. DOPA decarboxylase inhibitors suppressed the advent of the deposits, but prior denervation did not. Biochemical studies showed: (a) slices produced 2.2 nmol mg-1 protein, glomeruli 0.2 and cytosol 43 nmol. In absence of L-DOPA or in presence of DOPA decarboxylase inhibitors, DA production was suppressed. Prior denervation did not influence DA production; (b) DA synthesis increased with sodium concentration of the milieu (range 95 to 152 mmol). Adult spontaneously hypertensive rats (SHR) produced less DA than SD or normotensive Wistar-Kyoto, at any sodium concentration from 95 to 142 mmol. This discrepancy could be related to the pathogenesis of hypertension.
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PMID:Extraneuronal production of dopamine by kidney slices in normo and hypertensive rats. 367 50


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