Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The blocking of the creatinphosphokinase by 1-fluoro-2,4-dinitrobenzene (FDNB) allows to investigate the relationship between ATP-supply, contractility and relaxability of the frog's myocardium. In isotonically working isolated ventricles of frogs the time of work, systolic and diastolic volume, velocity of contraction and relaxation as well as the levels of CP, ATP, ADP and AMP were measured at different intervals until termination of each experiment. CP shows a small variation, ATP decreases to 60% and ADP + AMP increase for the same amount under FDNB during the development of a slight inhibition of contractility and a continuously growing inhibition and retardation of relaxation until systolic arrest. ATP content and volume of relaxation correlated strictly. The contracture and the diminished contractility are caused by the decrease of ATP, producing a lack of substrate for Ca transport and actin-myosin-ATPase. This models the course of events during an insufficiency like in angina pectoris and in myocardial infarction.
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PMID:[Mechanical characteristics of isotonic work and high-energy phosphates in frog ventricle after 1-fluoro-2,4-dinitrobenzene]. 31 Jun 11

Trapymin (TM) relaxed excised renal, coronary, pulmonary, femoral and mesenteric arteries and this relaxation was not antagonized by propranolol. The dose-response curve of TM was parallel to that of nitroglycerin and papaverine and steeper than that of dipyridamol or adenosine. TM exerted inotropic and chronotropic actions on excised rat atrium. TM was also effective through the oral route and the effectiveness tended to decrease slightly after repeated use for ten days. TM was effective on vasopressin induced angina in rats and electrocoagulation-induced myocardial infarction. TM suppressed adrenaline-induced arrhythmia but not CaCl2-induced arrhythmia. TM reduced catecholamine content in brain, adrenals and heart but had no influence on monoamine oxidase or dopamine-beta-hydroxylase. TM revealed ganglion-blocking and neuron-blocking actions in cervical ganglion in cats. With propranolol, TM-induced hyperglycemia and reduction in glycogen content in liver and heart was antagonized but TM-induced rise in free fatty acid in serum was not antagonized. Na+-K+ dependent ATPase of bovine heart and P/O ratio of mitochondria of rat heart was not influenced by TM. ADP-induced aggregation of platelets was antagonized by TM. These data indicate that TM induced coronary dilation is partly due to a papaverine like action and also to ganglion-blocking, neuron-blocking and anti-adrenergic action. On the other hand, TM possessed catecholamine release and cardiotonic action as related to beta-receptors.
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PMID:[Pharmacology of cornary dilator agent, trapymin. (2) Analysis of its mode of action]. 124 70

Despite the fact that numerous studies have been published regarding the possible presence in plasma of an endogenous Na-K pump inhibitor with a digitalis-like structure in essential hypertension, very little is known about this factor in heart disease in general, and in situations characterized by low cardiac output. We measured the ability of plasma obtained from the femoral vein to inhibit a human renal Na(+)-K+ ATPase before and immediately after percutaneous transluminal coronary angioplasty (PTCA) in 6 patients suffering from angina pectoris and severe coronary stenosis. Intraerythrocyte sodium and potassium concentrations were also measured simultaneously. Na(+)-K+ ATPase inhibition proved significantly greater after angioplasty as compared to basal activity (percentage inhibition: 31.5 +/- 7.8 vs 16.1 +/- 12.2). No significant changes in intraerythrocyte sodium and potassium were detected. Though we are not in a position to define the mechanism underlying the increase in the digitalis-like factor, a plausible hypothesis may be that the reduction in cardiac output during PTCA by raising cardiac pressures may stimulate the production of a factor of compensatory inotropic significance.
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PMID:Increase in plasma digitalis-like activity during percutaneous transluminal coronary angioplasty in patients with coronary stenosis. 216 10

The manifestations of cardiac involvement in hypertension include: (1) the development of hypertensive heart disease characterized by left ventricular hypertrophy (LVH), and (2) the consequences of coronary atherosclerosis, as angina pectoris, myocardial infarction, and sudden cardiac death. Whereas the former is directly related to increased blood pressure, the latter are sequelae of atherosclerosis per se, and hypertension acts only as a risk factor in this regard. This can partially explain why antihypertensive treatment is effective in diminishing the incidence of congestive heart failure, which is the final consequence of LVH, but is not very effective in preventing coronary complications. It is generally accepted about LVH that increased arterial pressure is the major stimulus to cardiac hypertrophy in hypertension; however, there are a lot of both quantitative and qualitative events suggesting that other factors beside blood pressure levels can modulate the development of LVH, in particular neurohumoral influences. From a morphological point of view, hypertrophy of the cardiac muscle is defined as an increase in the size of existing myocardial fibers. In most experimental models, myocardial hypertrophy is associated with myosin isoenzymatic changes, consisting in a shift from the faster migrating isoenzyme V1 to V3, a form that migrates more slowly. However these changes do not occur in all animal species and particularly in humans. In the hypertrophied human ventricle, a decreased ATPase activity of myofibrils was observed, probably related to changes in myosin light chains. Presently the changes in ATPase activity and in ventricular contractility do not still have a clear molecular basis in humans.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heart and hypertension. 252 4

The purpose of the present work was to evaluate the clinical efficacy and the mechanism of Yi-qi Huo-xue Injection (YHI) in treatment of coronary heart disease. YHI consists of Ginseng, Astragalus and Angelicae Sinensis. The 10% dextrose serves as a placebo. The results were as follows: 1. the frequency and severity of angina episodes were reduced by 90.63%; 2. the ischemic ST-T in ECG was improved in 56.25% of cases; 3. the tolerance to treadmill exercise was increased from 348.50 to 503.50 M.; 4. the left ventricular function was strengthened, PEP/LVET ratio reduced from 0.45 to 0.36, the activity of (Na(+)-K+) ATPase in myocardial cell membrane of rats inhibited by 19.2%; 5. the blood viscosity and erythrocyte electrophoretic time lowered; 6. the adhesion and aggregation of platelet in patients with CHD were inhibited by 27% and 59.4% respectively; 7. the plasma TXB2 level in CHD was reduced from 260.28 +/- 164.4 to 139.29 +/- 57.01 pg/ml; 8. the plasma 6-keto-PGF1 alpha level in CHD was increased from 33.45 +/- 22.5 to 57.48 +/- 13.1 pg/ml, and in rats from 185.77 to 366.33 pg/ml. The differences were all statistically significant (P less than 0.05-0.01) in comparison with the placebo group.
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PMID:Clinical and experimental studies of coronary heart disease treated with yi-qi huo-xue injection. 261 56

Perhexiline is a lysosomotropic agent which has proved to be very valuable to certain patients suffering from angina pectoris. However long-term administration of the drug may induce hepato- and neuro-toxicity. Using HTC cells (a rat hepatoma-derived cell line) whose plasma membranes were labeled with NaB[3H]4 after oxidation by NaIO4, endocytosis and recycling of labeled asialo-orosomucoid (ASOR) receptors were investigated in the presence of 50 mumols/l perhexiline maleate. The results demonstrate that the drug induces a significant decrease of the rate of both the internalization and the recycling of ASOR receptors. The mechanisms responsible for these effects have not yet been elucidated. However, the current findings may be related to the previously observed inhibitory effect of perhexiline on cellular (Na+, K+)-ATPase and Mg++-ATPase activities. Our findings would then reflect insufficient cellular energy production, resulting from depressed ATP hydrolysis in the presence of perhexiline.
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PMID:Effects of perhexiline maleate on asialo-orosomucoid receptor endocytosis and recycling in HTC cells. 261

Nisoldipine is a calcium antagonist that specifically blocks the slow or voltage-dependent calcium channel up to the highest concentrations. This mode of action has been confirmed in pharmacological studies on isolated organs, electrophysiological and binding studies, and by the measurement of transmembrane calcium transport. As with other dihydropyridine calcium antagonists, an interaction with intracellular calcium reservoirs and calmodulin seems to be of minor importance. The drug exhibits higher potency, longer duration of action, and a higher binding affinity in vitro and in vivo than nifedipine. In contrast to its vasodilating and spasmolytic activity, its negative inotropic effect occurs in vitro only after higher concentrations than after nifedipine. In whole animals a secondary positive inotropic effect occurs regularly owing to sympathetic counter-regulation. The influence of nisoldipine on cardiac stimulus formation and conduction is also very slight in anesthetized animals, and is completely eliminated in awake animals and humans by counter-regulation up to very high doses. The cardiac anti-ischemic action of nisoldipine has been demonstrated in various ischemia models and is probably based predominantly on its afterload-reducing properties in addition to its spasmolytic effect on the coronary arteries. Various other suspected effects, for which there are isolated indications, e.g., inhibition of thromboxane synthesis, preload reduction, interaction with the transport of adenosine, and normalization of the sarcolemmal Na+, K(+)-ATPase activity, are probably of subordinate importance. Its antihypertensive effect is explained primarily by lowering of the peripheral resistance. There are, however, some indications that nisoldipine exerts certain effects over and above pure vasodilation. The prevention of postischemic calcium overloading in the renal tubule epithelium and the natriuretic effect are probably of importance in the therapeutic action. Clinically, nisoldipine was found more potent and prolonged in its action in comparison with nifedipine. In comparative studies, nisoldipine, 10 mg once a day, was found equieffective with nifedipine 10 mg three times or 20 mg twice a day in angina or hypertension, respectively.
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PMID:The pharmacology of nisoldipine. 315 74

A major research program in the University of Maryland School of Medicine, Department of Pharmacology, in the 1930s was the preparation of a large number of sugar alcohols and their anhydrides as substitute carbohydrates for diabetic diets. As an outgrowth of this work, many of these polyols were converted to their nitrate esters and investigated for their vasodilating properties. The organic nitrates that were synthesized were examined for their potency, duration of action, and possible therapeutic use. It was demonstrated that, contrary to prior belief, the depressor and vasodilating action was exhibited by their own molecular structure and not through hydrolysis and reduction to nitrite. The search for the finer mechanism(s) of action on the vascular musculature showed that these nitrated polyols and their anhydrides inhibited arterial adenosine triphosphatase, although this enzyme inhibition did not correlate with pharmacologic activity. Today the mechanism of action of these drugs is not clearly understood at the cellular level. The 1,4:3,6-dianhydrosorbitol 2,5-dinitrate (isosorbide dinitrate) was synthesized, studied, and reported in 1940. It appeared to be a useful drug because blood levels of the unhydrolyzed ester were found to persist for long periods of time. Subsequent clinical studies in the 1960s demonstrated its prophylactic value in angina pectoris and its prolonged action as a therapeutic asset. In 1967 the mononitrate was shown to be formed in vivo when the dinitrate was administered orally and has been studied as the possible pharmacodynamically active moiety.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:History of the synthesis and pharmacology of isosorbide dinitrate. 389 78

The action on left ventricular function of Astragalus Membranaceus (AM), a Qi-tonic, in 20 patients with angina pectoris was studied by means of Doppler Echocardiogram (DEC). It showed that cardiac output increased from 5.09 +/- 0.21 to 5.95 +/- 0.18 L/min 2 weeks after AM was administered (P < 0.01), and no improvement of left ventricular diastolic function appeared. Adenosine triphosphatase activity was not inhibited by using AM, which was different from that of digitalis.
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PMID:[Action of Astragalus membranaceus on left ventricular function of angina pectoris]. 795 Jan 92

The basis for life is the ability of the cell to maintain ion gradients across biological membranes. Such gradients are created by specific membrane-bound ion pumps [adenosine triphosphatases (ATPases)]. According to physicochemical rules passive forces equilibrate (dissipate) ion gradients. The cholesterol/phospholipid ratio of the membrane and the degree of saturation of phospholipid fatty acids are important factors for membrane molecular order and herewith a determinant of the degree of non-specific membrane leakiness. Other operative principles, i.e. specific ion channels can be opened and closed according to mechanisms that are specific to the cell. Certain compounds called ionophores can be integrated in the plasma membrane and permit specific inorganic ions to pass. Irrespective of which mechanism ions leak across the plasma membrane the homeostasis may be kept by increasing ion pumping (ATPase activity) in an attempt to restore the physiological ion gradient. The energy source for this work seems to be glycolytically derived ATP formation. Thus an increase in ion pumping is reflected by increased ATP hydrolysis and rate of glycolysis. This can be measured as an accumulation of breakdown products of ATP and end-products of anaerobic glycolysis (lactate). In certain disease entities, the balance between ATP formation and ion pumping may be disordered resulting in a decrease in inter alia (i.a.) cellular energy charge, and an increase in lactate formation and catabolites of adenylates. Cardiac syndrome X is proposed to be due to an excessive leakage of potassium ions, leading to electrocardiographic (ECG) changes, abnormal Tl-scintigraphy of the heart and anginal pain (induced by adenosine). Cocksackie B3 infections, a common agent in myocarditis might also induce an ionophore-like effect. Moreover, Alzheimer's disease is characterized by the formation of extracellular amyloid deposits in the brain of patients. Perturbation of cellular membranes by the amyloid peptide during the development of Alzheimer's disease is one of several mechanisms proposed to account for the toxicity of this peptide on neuronal membranes. We have studied the effects of the peptide and fragments thereof on 45Ca2+-uptake in human erythrocytes and the energetic consequences. Treatment of erythrocytes with the beta 1-40 peptide, results in qualitatively similar nucleotide pattern and decrease of energy charge as the treatment with Ca2+-ionophore A23187. Finally, in recent studies we have revealed and published in this journal that a rare condition, Tarui's disease or glycogenosis type VII, primarily associated with a defect M-subunit of phosphofructokinase, demonstrates as a cophenomenon an increased leak of Ca2+ into erythrocytes.
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PMID:Imbalance of plasma membrane ion leak and pump relationship as a new aetiological basis of certain disease states. 1464 92


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