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

The goal of the present study was to compare the hemodynamic and biochemical effects of the renin inhibitor Ro 42-5892, the angiotensin converting enzyme inhibitor cilazapril, and the angiotensin II receptor blocker EXP132, the aldehyde derivative of DuP 753. The three drugs were evaluated in guinea pigs, previously treated with furosemide, using their maximal effective doses. Cilazapril decreased arterial blood pressure more than Ro 42-5892 and EXP132. In contrast, Ro 42-5892 and EXP132 had similar effects. The larger decrease of arterial pressure induced by cilazapril was not due to a larger decrease of angiotensin II in plasma and was not influenced by cyclooxygenase inhibition with indomethacin or by bradykinin antagonism with Hoe 140. After binephrectomy, most of the blood pressure-lowering effect of Ro 42-5892 disappeared. In contrast, cilazapril was still markedly effective, pointing to extrarenal effects. We conclude that in furosemide-treated guinea pigs, as opposed to previously published animal models, the decrease of arterial pressure induced by angiotensin converting enzyme inhibitors may be partly due to extrarenal effects not related to the renin-angiotensin system.
Hypertension 1992 Mar
PMID:Effects of renin-angiotensin system blockade in guinea pigs. 153 64

The synthesis of new 1,4-dihydropyridine derivatives containing novel substituent at the 2-position of the nucleus via the key intermediate 2-formyl-1,4-dihydropyridines (X), is described. The aldehydes (X) were prepared by hydrolysis of the acetals (IX) which were obtained from aryl aldehyde (V) and alkyl 4,4-dialkoxyacetoacetate (VI) by the Knoevenagel reaction and treatment with alkyl 3-aminocrotonate (VIII) according to the modified Hantzsch method. The formyl group of the aldehydes (X) was reactive enough to be converted to a variety of functional groups such as hydroxymethyl, cyano, substituted iminomethyl, carbamoyl, semicarbazone, substituted vinyl, ethynyl, and so on. In all of the novel compounds we prepared, 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridines (IV and XXII) were found to possess potent activities in preliminary biological evaluations on hypotension in normotensive rats and on an increase in coronary blood flow in pentobarbital-anesthetized dogs. Optimization research in order to obtain a more potent compound was accomplished in the 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridine series. We selected isopropyl 2-cyano-3-methoxycarbonyl-4-(3-nitrophenyl)-6-methyl-1,4-dihydropyridine -5-carboxylate (XXIIj) as a candidate compound for further biological evaluation studies. Fortunately, XXIIj (nilvadipine) has been accepted in clinical use for the treatment of hypertension.
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PMID:Studies on nilvadipine. I. Synthesis and structure-activity relationships of 1,4-dihydropyridines containing novel substituents at the 2-position. 181 11

It has been recently demonstrated that cortisol can be metabolized, producing 18-hydroxycortisol and 18-oxocortisol, following the same pathway by which corticosterone is transformed into 18-hydroxycorticosterone and aldosterone. The influence of a hydroxy group in the 17 alpha position of aldosterone or an aldehyde (actually 11-18 hemiacetal) in the 13-methyl of cortisol on the mineralocorticoid and glucocorticoid activities were studied and compared with the parent steroids. The ability of 18-oxocortisol to complete with [3H]aldosterone for binding to the cytosol receptor of rat renal slices was 8.1% in comparison to unlabeled aldosterone. The addition of a specific glucocorticoid 11 beta, 17 beta-dihydroxy-17 alpha-pregnane-1,4,6- trien-20-yn-21-methyl-3-one decreased this binding to 5.6%. The ability of 18-oxocortisol to compete with [3H]dexamethasone for binding to the renal cytosol receptor was 0.2% that of unlabeled dexamethasone and in the HTC whole cell assay was 1.06% and 3.8% that of unlabeled dexamethasone and cortisol, respectively. The mineralocorticoid activity of 18-oxocortisol in the adrenalectomized rat bioassay was 0.6% that of aldosterone. The glucocorticoid activity in in vitro bioassays was 3.1% compared with that of a cortisol when the induction of tyrosine aminotransferase in HTC cells was measured and 4% when the inhibition of fibroblast L-929 growth was measured. The significance of 18-oxocortisol in the pathogenesis of the hypertension in patients with primary aldosteronism is still unclear.
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PMID:Receptor binding and biological activity of 18-oxocortisol. 285 75

The clinical symptoms and signs, certain metabolic aspects (including ethanol, acetaldehyde and glucose concentrations in plasma) and hemodynamic parameters (cardiac rate, blood pressure and cardiac output) were assessed in 16 ambulatory alcoholics (3 female, 13 male, average age 46 years) following pretreatment with disulfiram (total dose 1.2 to 2.4 g) and oral administration of 0.2 g ethanol 94% per kg body weight. Since the only selection criterion for inclusion was a diagnosis of alcohol dependence (DSM III, 303.9), the group was heterogeneous and exhibited a variety of concomitant diseases such as alcoholic liver disease in 9, chronic bronchitis in 5 and arterial hypertension in 3. Whereas peak plasma alcohol concentrations were comparable (median: 0.33 mg/ml; range: 0.19 to 0.40) in all subjects, peak acetaldehyde levels varied over 40-fold (median 5.1 micrograms/ml; range: 0.2 to 8.8). In consequence, there were marked interindividual differences in cardiovascular reaction, in contrast to the virtually constant finding of flush, palpitations and dyspnoea. Since the decrease in peripheral vascular resistance (to a median of 46% of control) was only in part compensated by increased cardiac output (median: 161%), both systolic and diastolic blood pressures were reduced by 30 and 45 mm Hg respectively. In 4 patients systolic pressure fell to shock levels (less than 70 mm Hg). The presumed toxic effect of acetaldehyde is again supported by close correlations between acetaldehyde plasma concentrations and the changes in blood pressures and peripheral resistances. We were able to demonstrate that disulfiram-induced inhibition of hepatic microsomal function - measured with the aminopyrine breath test - predicts the expected acetaldehyde peak levels following ethanol administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Cardiovascular and metabolic changes in the antabuse-alcohol reaction: basis for the diagnosis of degree of severity]. 354 9

These experiments were undertaken to study the effect of the interaction of the antihypertensive agent guanethidine and two aldehydes possessing sympathomimetic activity on the blood pressure of spontaneously hypertensive rats (SHR). Acetaldehyde, when administered iv to acutely guanethidine-pretreated (15 mg/kg) SHRs under urethane anesthesia, caused a potentiated pressor response in the dose range of 3 to 40 mg/kg. When administered iv to chronically guanethidine-pretreated SHRs, a pressor response was noted at low doses and a depressor response at high doses. Acrolein (0.05 to 0.5 mg/kg) produced a pressor response at low doses and a depressor response at high doses in both acutely and chronically guanethidine-pretreated SHRs. Pressor responses, particularly to acetaldehyde, may be due to an enlarged tyramine-releasable pool, hyperreactivity of alpha adrenergic receptors of SHRs, or guanethidine inhibition of norepinephrine reuptake. Depressor responses to high doses of aldehydes may be attributed to vagal stimulation or direct vasodilation. It is concluded that there is a significant interaction between the aldehydes and guanethidine which may have implications for someone undergoing treatment with guanethidine for hypertension while being exposed to acetaldehyde and related compounds from ethanol and tobacco smoke.
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PMID:The effects of acetaldehyde and acrolein on blood pressure in guanethidine-pretreated hypertensive rats. 685 85

Physical, neurological and psychological examinations as well as laboratory tests were performed in the group of 147 workers, engaged in the production of chlorine, acetic aldehyde and soda lye, exposed to metallic mercury vapours and in the control group (n = 49). In the evaluation of laboratory tests, morphology of peripheral blood, liver function tests and lipid balance were analysed in the first part of the work. Electroencephalography, electrocardiography and chest X-ray were also performed as auxiliary examinations. There was a certain percentage of cases with symptoms of organic damage of the brain mostly in the form of cerebellar syndrome. Psychological organic tests proved to be of little value in the evaluation of effects of exposure to mercury. The results suggest that occupational exposure to metallic mercury vapours can enhance the risk of hypertension and myocardial failure. Harmful effect of occupational exposure to metallic mercury vapour on the respiratory and haemopoietic systems as well as on the liver and lipid balance was not observed.
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PMID:[Examination of health effects after exposure to metallic mercury vapors in workers engaged in production of chlorine and acetic aldehyde. I. Evaluation of general health status]. 763 28

Chronic alcohol abuse may lead to hypertension by stimulating the activity of the renin angiotensin system (RAS). While there are reports on the alcohol associated increase of angiotensin II in rats and increases of plasma renin activity in rats and human alcoholics, the exact mechanisms of stimulation of the RAS activity is not clear. This study provides evidence for a biochemical interaction of acetaldehyde, the primary oxidative metabolite of ethanol, upon bilaterally nephrectomized (NEPEX) rat plasma that contains significant quantities of angiotensinogen and lacks active renin. Rat plasma served as the source of renin in this study. Preincubation of NEPEX plasma with 0.2 M acetaldehyde at 4 degrees C for 2 h resulted in a 21% increase in the angiotensin I (A I) formation by the rat plasma renin and 27% increase in the A I formation by the trypsinized rat plasma renin. When the rat plasma which contains modest quantities of endogenous angiotensinogen in addition to renin was preincubated with 0.2 M acetaldehyde at 4 degrees C for 2 h, the rate of A I formation was increased by 10%. Equivalent amounts of ethanol did not modify the rate of A I generation when added to NEPEX plasma or rat plasma. These results suggest the possibility of a biochemical interaction of acetaldehyde with the renin substrate which may enhance the activity of the RAS cascade, thereby contributing to hypertension in chronic alcoholics.
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PMID:Interaction of acetaldehyde with plasma proteins of the renin-angiotensin system. 786 50

Increased alcohol consumption causes hypertension and leads to higher death rates by hemorrhagic strokes. About half of the Japanese population have inactive low Km aldehyde dehydrogenase (ALDH2), which metabolizes acetaldehyde to acetic acid at very low concentrations, leading to severe pharmacological effects of aldehyde when drinking alcohol. We determined persons with inactive ALDH2 using a ethanol patch test. All male workers (n + 163), aged from 21 to 62 years in one factory in Japan took part. They were divided into two groups by alcohol consumption (nondrinkers, light drinkers of < 32 ml/l ethanol per day and moderate to heavy drinkers of > or = 32 ml ethanol per day). The prevalence of persons with inactive ALDH2 was 52.1%. The prevalence of moderate to heavy drinkers among persons with inactive ALDH2 was significantly lower than that among those with active ALDH2 (23% and 41%, respectively: P < 0.05). No significant differences of BP were observed between ALDH2 inactive and active groups at the same consumption of alcohol. This study showed a significant relationship between categories of alcohol use and SBP and DBP (P < 0.05, respectively) controlled for age and body mass index. The mechanism by which alcohol use elevates BP is unlikely to be related to the inactive ALDH2. However, inactive ALDH2 may act as a protective factor against hypertension by reducing alcohol consumption.
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PMID:Low-Km aldehyde dehydrogenase deficiency does not influence the elevation of blood pressure by alcohol. 800 21

It has been shown that alcohol administration causes baroreceptor reflex inhibition. The site of action of alcohol could reside anywhere within the baroreceptor reflex arc. Therefore, the goal of this study was to determine the effects of acute administration of alcohol on carotid sinus baroreceptor discharge characteristics. In pentobarbital-anesthetized dogs, the carotid sinus was isolated and perfused. Single unit baroreceptor discharge was recorded from the carotid sinus nerve along with carotid sinus diameter using sonomicrometry. Carotid sinus pressure-baroreceptor discharge and carotid sinus pressure-diameter curves were constructed. Perfusion of the carotid sinus with alcohol (100 mmol/L) significantly decreased the pressure threshold from 91.1 +/- 2.8 to 86.4 +/- 2.9 mm Hg (p < 0.05) and increased the peak discharge rate from 45.8 +/- 3.4 to 52.8 +/- 3.6 spikes per second (p < 0.01). The same phenomenon was seen during perfusion of the carotid sinus with acetaldehyde (2.5 mmol/L) but was not seen during perfusion with acetate (2.5 mmol/L). During perfusion of the carotid sinus with alcohol, the carotid sinus pressure-carotid sinus diameter relation did not change. The baroreceptor sensitization induced by alcohol is not an endothelium-dependent mechanism, because endothelial denudation did not block this alcohol-induced effect. Measurement of the duration of postexcitatory depression of carotid sinus baroreceptors, which is related to Na+,K(+)-ATPase activity, showed that perfusion of the carotid sinus with alcohol or acetaldehyde significantly reduced the duration of postexcitatory depression, indicating that the alcohol- and acetaldehyde-induced effect on baroreceptor discharge is most likely mediated by an inhibition of Na+,K(+)-ATPase.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1993 May
PMID:Acute alcohol administration stimulates baroreceptor discharge in the dog. 849 3

Despite intense research efforts, the etiology of primary hypertension remains ill-defined. During our work on molecular influences of lifestyle factors on hypertension, the question arose to what extent cellular and molecular events could be involved in alcohol-induced hypertension. There is increasing evidence that alcohol initiates central as well as peripheral reactions which in a synergistic manner have a hypertensive action. Thus, alcohol diminishes the baro (presso) reflex by interacting with receptors in the brain stem, i.e. nucleus tractus solitarii and rostral ventrolateral medulla. In addition, alcohol induces an increased sympathetic outflow, most probably linked to secretion of corticotropin-releasing hormone. The increased sympathetic outflow is expected not only to induce adrenoceptor-mediated reactions (vasoconstriction, heart rate increase) but to stimulate oxidation reactions. Deleterious peripheral actions result from acetaldehyde which binds to macromolecules if the abundance of cysteine and glutathione is limited. This acetaldehyde induced reduction of low molecular weight thiol compounds can be interpreted as "oxidative stress" which has various unfavourable consequences. The hypertensive action of alcohol should be taken into account when discussing its potential protective influence on coronary risk.
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PMID:[Hypertension and alcohol: central and peripheral mechanisms]. 880 6


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