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

The interaction between noradrenergic and serotonergic mechanisms on the central regulation of blood pressure in the rat was studied, using central experimental hypertension produced by chemical lesions of the locus coeruleus (LC) with 6-hydroxydopamine (6-OHDA). The hypertension (LC-hypertension) was blocked by pretreatment with 6-OHDA intraventricularlly administered and also with desipramine. An increase of serotonin (5-HT) turnover in the cortex and especially in the spinal cord was revealed in the hypertension. Intraperitoneally administered para-chlorophenylalanine elevated blood pressure and reduced 5-HT and 5-hydroxyindole acetic acid content in the cortex and especially in the spinal cord, indicating a decrease 5-HT turnover. Intraventricularlly administered 5, 6-dihydroxytryptamine (5, 6-DHT) resulted in only bradycardia but not an elevation in blood pressure and did not block the development of LC hypertension, and lowered 5-HT content in the cortex and especially in the spinal cord. Intraspinally administrated 5, 6-DHT evoked mild but significant elevation in blood pressure but not in heart rate, and lowered 5-HT content only in the spinal cord. Furthermore, the disappearance of the LC was histologically observed in the rats with LC hypertension. The results of these experiments demonstrate that (1) LC hypertension is probably due to a specific lesion of the LC with 6-OHDA, (2) LC hypertension is accompanied by an increase of 5-HT turnover in the cortex and especially in the spinal cord, which may participate in a depressor function in LC hypertension, (3) ablation of bulbospinal serotonergic neurons produce mild elevation in blood pressure. (4) the balance between the activity of central noradrenerfic and serotonergic neurons may play a role in maintaining normotension, and their unbalance may induce hypertension.
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PMID:Interaction between noradrenergic and serotonergic mechanisms on the central regulation of blood pressure in the rat: a study using experimental central hypertension produced by chemical lesions of the locus coeruleus. 15 55

Effect of tolmetin sodium on the pain-like responses caused by various nociceptive stimuli was examined in experimental animals. Tolmetin sodium showed a potent inhibitory activity on the acetic acid-induced writhing in mice and rats, and its potency, (ED50 = 23.4 and 3.01 mg/kg, p.o.) was about 2.4--10.3 times that of ibuprofen and aspirin. The hypertension induced by intraarterial injection of bradykinin toward the spleen of dogs was inhibited by tolmetin sodium (ED50 = 80 mg/kg, i.v.), but the hypertension by a simultaneous injection of bradykinin and PGE1 was not inhibited by tolmetin sodium and sulpyrine, though pentazocine inhibited both hypertensions. The pain-like response caused by pressing mechanically the inflamed paws or joints of rats induced by kaolin-carrageenin or adjuvant was inhibited by tolmetin sodium (30--100 or 20--40 mg/kg, p.o., respectively), and the potency was approximately equal that of ibuprofen and phenylbutazone. Tolmetin sodium produced a significant inhibition of the pain-like response induced by electrical stimulation of tooth pulp of dogs, but showed no effect when the methods of Haffner and D'Amour-Smith were applied to mice. Anti-writhing action of tolmetin sodium was not antagonized by naloxone. From these results, it was concluded that tolmetin sodium has a potent inhibitory activity on the pain-like responses induced by the chemical nociceptive stimuli and by the mechanical pressure stimulus of the inflamed tissue, especially on the writhing. The analgesic activity probably involves a peripheral mechanism.
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PMID:[Analgesic activity of a non-steroidal anti-inflammatory agent, tolmetin sodium in experimental animals (author's transl)]. 53 31

Dichlormagnesium-aspartate-hydrochloride was given to 12 patients with mild hypertension in antihypertensive indication at a dose of 10.5 mmol Mg2+/day for 3 months. Blood pressure normalized (from 161.7 +/- 3.4/95.8 +/- 0.8 mmHg to 140.4 +/- 4.0/81.7 +/- 0.9 mmHg, after the third month (p < 0.01). While no changes in Mg2+ concentration in serum were observed in patients with normomagnesaemia, in hypomagnesaemic patients vS-Mg level normalized. Renal excretion of Mg2+ increased: from 3.41 +/- 0.36 before to 5.7 +/- 0.57 mmol Mg2+/24 h after treatment, p < 0.01. Mean plasma serotonin (5HT) concentration showed no changes, although a trend towards an increase in platelet 5HT content was observed. Elevated pre-treatment plasma 5-hydroxyindole acetic acid (5HIAA) concentrations normalized (from 137.29 +/- 20.3 to 78.96 +/- 31.64 nmol/l after the third month, p < 0.05). These findings point to a platelet-stabilizing effect of Mg2+. Fractional excretion of 5HIAA increased (from 1.42 +/- 0.27 to 5.4 +/- 1.22 after treatment, p < 0.01) while mean urinary 5HIAA excretion remained unchanged. It is deduced that a) total body 5HT and 5HIAA production was not affected; b) a long-term supplementation of Mg2+ stimulates the transport of 5HIAA in proximal tubules and, probably, intrarenal 5HIAA synthesis. A functional block in 5HT metabolism under Mg2+ treatment is anticipated. Thus, Mg2+ supplementation has renal and extrarenal effects that are important in treating hypertension and its complications.
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PMID:Anti-hypertensive treatment with magnesium-aspartate-dichloride and its influence on peripheral serotonin metabolism in man: a subacute study. 128 56

We present a case in which a 39-year-old woman with correctable bilateral renovascular hypertension did not show abnormality during post-captopril technetium-99m dimercaptosuccinic acid (DMSA) study. Post-captopril 99mTc-diethylene triamine penta-acetic acid (DTPA) scintigraphy revealed the adverse effect of a stenosis of the artery supplying the upper part of her left kidney but failed to uncover the existence of severe multiple narrowings of the right renal artery. After bilateral renovascular reconstructive surgery, the hypertension completely disappeared. This case illustrates that DTPA may be more efficacious than DMSA in the detection of segmental loss of renal function induced by angiotensin converting enzyme inhibition.
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PMID:Technetium-99m diethylene triamine penta-acetic acid and dimercaptosuccinic acid in the detection of a segmental branch stenosis of the renal artery by captopril renography. 131 69

Pretreatment (15 min) of male rats with gepirone given parenterally (10 mg/kg i.p.) or intracranially into the dorsal raphe nucleus (14 or 21 micrograms) blocks the rapidly reversible increase in brain tryptophan hydroxylase activity and 5-hydroxyindolamine acetic acid tissue levels seen in vitro after 1-h acute sound stress. Chronic gepirone treatment over 28 days (40 mg/day s.c.) prevents the stable enzyme activity increase induced by repeated sessions of sound stress, and the rapidly reversible increase always observed following sound stress. The gepirone metabolite, 1-(2-pyrimidinyl)-1-piperazine, is inactive in each of these experiments. Transient blood pressure elevations occur with each sound presentation, but no persistent hypertension is observed with repeated sound-stress exposures. Gepirone may block the sound stress-induced biochemical increases by its inhibition of serotonergic neuronal firing in the dorsal raphe nucleus that is mediated by its agonist action at the somatodendritic (5-HT1A) autoreceptors.
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PMID:Effect of gepirone on increases in tryptophan hydroxylase in response to sound stress. 137 31

The purpose of this study was to clarify the selectivity and specificity of noninvasive procedures for diagnosis of clinically suspected posttransplant renovascular hypertension. We prospectively investigated 25 renal transplant recipients with arterial hypertension and clinically suspected stenosis of the graft artery (8 female and 17 male patients; ages 45 +/- 15 years). We performed a captopril test with 25 mg captopril (n = 25), renography with technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) before and after angiotensin-converting enzyme (ACE) inhibition with determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) (n = 23) and color-coded duplex ultrasonography of the transplant kidney vessels (n = 24). Renal transplant artery stenosis (RTAS) was excluded by renal arteriography in 20 patients and by operative evaluation or clinical follow-up in 5 patients. We identified 4 patients with RTAS and renovascular hypertension. The noninvasive methods showed the following results (sensitivity/specificity): (1) captopril test: 75%/67%; (2) renography combined with ACE-inhibition: 75%/84%; and (3) color-coded duplex ultrasonography: 100%/75%. We conclude that in patients with clinical evidence of RTAS most noninvasive diagnostic procedures are not sufficiently accurate to exclude the diagnosis. Only color-coded duplex ultrasonography did not fail to detect all patients with RTAS and may act as a screening test. Intraarterial renal angiography remains the most reliable and as-yet indispensable diagnostic test for transplant recipients to rule out RTAS.
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PMID:Noninvasive procedures for diagnosis of renovascular hypertension in renal transplant recipients--a prospective analysis. 144 Aug 54

A two week administration of the glucocorticoid betametasone to male Wistar rats produced a mild hypertensive state. The brain of these rats showed some significant changes in amine and metabolite content with respect to normotensive controls. Epinephrine and metanephrine were increased in the rostral ventrolateral medulla and in the preoptic area. Epinephrine also increased in the septal area. Normetanephrine decreased in the rostral ventrolateral medulla. Dopamine and homovanillic acid increased in septal and preoptic areas. Dopamine alone increased in rostral ventrolateral medulla. Serotonin and 5-hydroxyindole-3-acetic acid increased in the septal area and dorsal medulla. These changes suggest significant alterations in the aminergic activity of the brain circuitry known to regulate cardiovascular functions; the changes may play a basic role in the development and maintenance of glucocorticoid-induced hypertension.
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PMID:Brain amines in glucocorticoid-induced hypertension in the rat. 162 93

Metabolites of neurotransmitters of dopamine, homomovanillic acid (HVA), and of serotonin, 5-hydroxyindole acetic acid (5-HIAA), were assessed in cerebrospinal fluid by the method of high pressure liquid chromatography with electrochemical detection. The HVA concentration in cerebrospinal fluid rose markedly in a two-month-old infant with intracranial hypertension caused by a communicating hyporesorptive hydrocephalus following administration of tyrosine, the precursor of dopamine. The 5-HIAA concentration in cerebrospinal fluid rose significantly in a 20-month-old boy with epilepsy and arrested psychomotor development after administration of 5-hydroxytryptophan, the precursor of dopamine. Biochemical normalization of concentrations of neurotransmiteed metabolites did not lead to changes in the clinical condition of the children.
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PMID:[The effect of amino acids on neurotransmitter metabolites in the cerebrospinal fluid]. 171 69

A number of studies show that atrial natriuretic peptide (ANP) raises renal sodium excretion with a concomitant increase in glomerular filtration rate (GFR) in both experimental animals and normal humans. Studies using indirect evaluation of GFR have provided less consistent results in hypertensive patients. We studied the effects of intravenously administered (iv) alpha-human ANP on GFR in patients with hypertension by a radionuclide technique using technetium 99m diethylenetriaminepenta-acetic acid. In six patients (ANP group), GFR was determined under control conditions, during iv ANP (initial bolus of 0.5 micrograms/kg followed by a 21-min maintenance infusion at 0.05 micrograms.kg-1.min-1) and during a recovery phase. In six other patients (control group), GFR was determined under control conditions, during saline iv infusion and during recovery. The two groups did not differ with respect to age, sex, basal blood pressure, heart rate or GFR. In the ANP group, the infusion of the peptide induced a significant decrease of mean blood pressure (from 133 +/- 5 to 120 +/- 5 mmHg, P less than 0.01), no change in heart rate and a significant increase in GFR (from 104 +/- 4 to 125 +/- 5 ml/min, P less than 0.01). During recovery, blood pressure, heart rate and GFR were not different from the values recorded under control conditions. No changes in blood pressure, heart rate or GFR (from 106 +/- 5 to 108 +/- 5 ml/min, n.s.) were detected during saline infusion in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of atrial natriuretic peptide on glomerular filtration rate in essential hypertension: a radionuclide study. 182 83

Research in nephrologic nuclear medicine is presently concentrated in two well-defined areas: interventional procedures and the use of mercaptoacetyltriglycine. The ongoing evaluation of mercaptoacetyltriglycine continues to be a source of interesting research activity, with the distribution volume and the extent of hepatic excretion remaining points of discussion. This tracer permits quantitative determination of renal function. As an imaging agent, mercaptoacetyltriglycine compares favorably with hippurate and with diethylenetriamine penta-acetic acid, particularly in evaluating renal insufficiency. Renal function studies obtained during pharmacologic or physiologic intervention dominate research in hypertension and obstructive uropathy. Angiotensin-converting enzyme inhibition improved the renographic detection of renovascular lesions. Interventional renography with angiotensin-converting enzyme inhibition or ergometric exercise were both capable of generating useful prognostic data on the posttherapy blood pressure response in patients with renovascular hypertension. Interventional diuretic renography with furosemide permits surgical intervention to be reserved for organs at immediate risk because the degree of obstruction and the extent of renal function compromise are easily recognized.
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PMID:Renal studies in nuclear medicine. 183 42


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