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

We studied the effect of indole-3-pyruvic acid (IPA) on systolic blood pressure of normotensive, spontaneously hypertensive, DOCA + salt hypertensive, and Grollman hypertensive rats. Experiments were also carried out in order to investigate whether IPA may influence the development of hypertension in spontaneously hypertensive rats. Age-matched normotensive, spontaneously hypertensive, DOCA + salt hypertensive, and Grollman hypertensive rats treated with N-methylglucamine, were used as controls. Acute oral (up to 50 mg/kg) and intravenous (5 mg/kg) administration of IPA did not change systolic blood pressure in any models of hypertension. By contrast, a repeated administration of IPA (100 mg/kg/day, by oral gavage for 10 days) significantly decreased systolic blood pressure in all models of hypertension, while it elicited no significant effect in normotensive rats. Moreover, when IPA was given daily to 5-week-old spontaneously hypertensive rats for 7 weeks, it partially inhibited the development of hypertension. In addition, chronic administration of IPA caused enhanced levels of tryptophan and 5-hydroxyindoleacetic acid in the cortex and diencephalon. Brainstem serotonin content in both normotensive and spontaneously hypertensive rats was also enhanced by IPA treatment. Our results suggest that IPA lowers blood pressure in different rat models of hypertension and this effect seems to be correlated with an increase in cerebral serotonin metabolism.
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PMID:Antihypertensive activity of indolepyruvic acid: a keto analogue of tryptophan. 168 65

A number of reports of potential etiologic agents of localized and systemic scleroderma appeared in the past year, including alterations in tryptophan metabolism, use of appetite suppressants, and exposure to silicone. An infectious agent, Borrelia burgdorferi, was found not to be implicated in localized scleroderma. The improvement in outcome of systemic scleroderma complicated by renovascular hypertension was highlighted in several papers, as was the emerging importance of cardiac and pulmonary involvement. Recent advances in the early detection and evaluation of cardiac and pulmonary complications of scleroderma are discussed.
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PMID:Clinical aspects of localized and systemic scleroderma. 177 53

This study was designed to assess the effect of chronic dietary administration (2.5 and 5.0% by weight) of the neutral amino acid, L-tryptophan, on the development of hypertension during chronic exposure to cold. In addition, a warm-adapted and cold-treated control group receiving unsupplemented food were used. Chronic administration of the lower dose of L-tryptophan (850 mg/day) prevented the elevation of blood pressure attenuated cardiac hypertrophy, and had no effect on body weight during exposure to cold. The higher dose of L-tryptophan (1,690 mg/day) attenuated the rate of blood pressure increase, did not affect cardiac hypertrophy, attenuated the gain in body weight, and increased the urinary output of epinephrine. Thus, this dose may be associated with some toxicity. Both doses of tryptophan failed to prevent certain other responses characteristically occurring during exposure to cold: i.e. increased weight of the kidneys, adrenal glands and brown adipose tissue; increased food and water consumption; increased dipsogenic responsiveness to angiotensin II, and increased plasma aldosterone concentration. The results indicate that chronic dietary administration of L-tryptophan (850 mg/day) can prevent the development of cold-induced hypertension, as it can in all other models of hypertension tested thus far in rats.
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PMID:Effect of chronic dietary treatment with L-tryptophan on the development of cold-induced hypertension in rats. 194 99

Dahl salt-sensitive rats are inbred on the basis of their tendency to develop hypertension when placed on a high salt diet. The present study investigated the effects of chronic dietary tryptophan (trp) at 50 g/kg food on the development of hypertension in these animals under conditions of both normal and elevated dietary salt. Dietary trp attenuated the development of hypertension in inbred Dahl salt-sensitive (DS/JR) rats and had no effect upon the patterns of development of systolic blood pressures in the normotensive controls, the inbred Dahl salt-resistant (DR/JR) rat and the outbred parental Sprague Dawley (SD) rat. Cardiac hypertrophy, which is associated with Dahl salt-induced hypertension, was blocked by the high trp diet. Further work will be necessary to elucidate the mechanisms by which dietary trp protected against the development of hypertension and cardiac hypertrophy in DS/JR rats.
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PMID:Effect of dietary tryptophan on the development of hypertension in the Dahl salt-sensitive rat. 213 37

Scleroderma developed in six women who were taking L-tryptophan. Fasciitis and morphea were most common, but one patient had pleural effusion, hypertension, and signs of cardiac and kidney failure. In five patients the biopsy findings were characteristic of scleroderma; the sixth patient had Crohn's disease and developed fasciitis; her biopsy specimen showed inflammatory arteritis. All patients' conditions improved after cessation of their L-tryptophan intake, initiation of corticosteroid therapy, or both. These findings confirm previous data that show altered tryptophan-kynurenine metabolism in some patients with scleroderma and fasciitis, particularly with tryptophan loading.
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PMID:Scleroderma and L-tryptophan: a possible explanation of the eosinophilia-myalgia syndrome. 221 43

Four-week-old inbred Dahl salt-sensitive (DS/JR) and Dahl salt-resistant (DR/JR) rats were placed on an 8% salt diet with or without a supplemental 2.5% tryptophan (Trp). Blood pressures were monitored for the next 5 weeks. Urine volumes and ion concentrations were measured during the 6th week. Blood pressures of DS/JR rats on control diets elevated rapidly and markedly, whereas pressures of DS/JR rats on the Trp-supplemented diet were not significantly elevated over those of DR/JR rats. Pressures of DR/JR rats were unaffected by Trp supplementation. Urinary sodium was significantly greater in DR/JR rats compared with DS/JR rats and was unaffected by Trp supplementation. This suggests that the antihypertensive effect of Trp was not at the level of the kidney. We conclude that dietary Trp blocks the development of hypertension in DS/JR rats maintained on a high salt diet.
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PMID:Prevention of Dahl salt-induced hypertension by chronic dietary tryptophan. 228 87

Hypotensive responses to tryptophan and 5-hydroxytryptophan infusions were studied in normotensive male Sprague-Dawley rats. Results showed that 5-hydroxytryptophan but not tryptophan lowered pressure in a dose dependent way in direct relation to the production of brain serotonin and 5-HIAA. Intrinsic release of serotonin from brain was also studied during periods of induced hypertension and hypotension. Brain monoamine responses to blood pressure changes induced by intravenous phenylephrine and nitroprusside were measured in dorsal raphe nucleus and nucleus tractus solitarius by in vivo electrochemistry. Results showed that 5-HIAA was increased during drug induced hypertension and during reflex hypertension which followed a period of hypotension. These changes were blocked by sinoaortic denervation indicating that these central serotonergic neurons are responding to increased pressure sensed by baroreceptors. Therefore, serotonin has a role in blood pressure regulation as a pharmacologic agent and as a neurotransmitter in homeostatic control of pressure.
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PMID:Brain serotonin and blood pressure regulation: studies using in vivo electrochemistry and direct tissue assay. 241 30

Serotonin levels and turnover were analyzed in discrete forebrain and mesencephalic nuclei of young (4-week-old) and adult (14-week-old) spontaneously hypertensive rats and age-matched normotensive control Wistar Kyoto rats. Most changes observed were age-dependent, and occurred only in young, early hypertensive rats. Both serotonin levels and the accumulation rate of 5-hydroxy-tryptophan after L-amino acid decarboxylase inhibition were higher in the nuclei periventricularis and paraventricularis of the hypothalamus of young hypertensive rats than in controls. In addition, 4-week-old spontaneously hypertensive rats showed higher 5-hydroxytryptophan accumulation rates in the nuclei supraopticus and dorsomedialis of the hypothalamus than controls. The only difference in serotonin metabolism found in adult hypertensive rats was high serotonin concentration in the median eminence of the hypertensive animals. Our results suggest the presence of anatomically specific, age-dependent alterations in serotonin metabolism, localized to selected hypothalamic nuclei in young hypertensive rats. These data support a role for the hypothalamic serotonin in the development of the spontaneous (genetic) hypertension in the rat.
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PMID:Serotonin turnover in discrete hypothalamic nuclei and mesencephalic raphe nuclei of young and adult spontaneously hypertensive rats. 242 65

Behavioral state instability in growth-retarded fetuses might be related to a decrease in serotonine production. Tryptophan maternal and cord blood values after elective cesarean section have been investigated by means of high performance liquid chromatography in 20 growth-retarded fetuses due to pregnancy-induced hypertension (PIH) and 20 normal pregnancies as control group. The feto-maternal ratio of tryptophan is significantly higher in normal fetuses than in PIH growth-retarded fetuses (p less than 0.001). Behavioral states have been determined 1 week and just before cesarean section. Values of 1F, 2F, 3F and 4F differ in the 2 groups (p less than 0.001). A higher percentage of non-coincidences (p less than 0.001) and state interruptions (p less than 0.001) is found in PIH fetuses. A significant correlation is demonstrated between the increase of non-coincidences and decrease in the feto-maternal Trp ratio (p less than 0.001).
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PMID:Tryptophan availability and fetal behavioral states. 248 11

Hypertension developed within 5 weeks in uninephrectomized rats administered deoxycorticosterone acetate (DOCA, 30 mg/kg, s.c., weekly) and given isotonic saline to drink. Chronic dietary administration of tryptophan (50 g/kg food) reduced intake of saline solution and prevented the elevation of systolic blood pressure induced by treatment with DOCA alone. Treatment with tryptophan also protected against the reduction in urinary concentrating ability during a 24 h dehydration that is characteristic of DOCA-treated rats. Other tests were carried out to assess the responsiveness to the beta-adrenergic agonist, isoproterenol. The tests included measurement of drinking and heart rate following acute administration of isoproterenol. The characteristically depressed drinking response of DOCA-treated rats to acute administration of isoproterenol was returned to that of untreated controls by chronic treatment with tryptophan. However, the reduced chronotropic response of the heart of DOCA-treated rats to administration of isoproterenol was unaffected. The cardiac hypertrophy characteristic of DOCA-treatment was attenuated significantly by chronic treatment with tryptophan. These results suggest that tryptophan provides significant protection against the development of DOCA-induced hypertension, polydipsia, and cardiac hypertrophy in rats. The mechanism by which tryptophan protects is unknown and requires additional study.
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PMID:Prevention of DOCA-induced hypertension in rats by chronic treatment with tryptophan. 295 Oct 40


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