Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments were conducted on rats; in depression of blood cholinesterase activity by 68.6 percent phthalafos proved to decrease the myocardial nicotinamide coenzymes content on account of reduction in the amount of the oxidized forms. In the liver phthalafos diminished the content of oxidized and reduced forms of nicotinamide coenzymes, decreased the level of adenylic nucleotides chiefly at the expense of ATP. Diproxim prevented the changes caused by phthalafos in blood cholinesterase reactivation to 47.5 percent. It is supposed that the capacity of diproxim to normalize the oxidative processes in the cell by acting upon the nicotinamide coenzymes and adenylic nucleotides underlies its antidote action.
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PMID:[Effect of dipyroxime on the concentration of nicotinamide coenzymes and adenylate nucleotides in the myocardium and liver of rats poisoned with phthalophos]. 2 70

The aerobic uptake of inorganic ions, such as 86Rb+ or 125I-, by submitochondrial particles, is about one order of magnitude lower than the uptake of organic ions, such as acridines or 8-anilino-1-naphthalene sulphonate. The values of deltapH, the transmembrane pH differential, and deltapsi, the transmembrane membrane potential are between 60 and 100 mV when calculated on the inorganic ions and between 150 and 240 mV when calculated on the organic ions. The discrepancy between the deltapH and deltapsi values from organic and inorganic ions is large at high but not at low ion/protein ratios. 2. In the absence of weak bases and strong acids the values of deltamuH, the proton electrochemical potential difference, are close to 100 mV and the magnitude of deltapH and deltapsi are similar. Weak bases decrease deltapH and enhance deltapsi. Strong acids decrease deltapsi and enhance deltapH. Interchangeability of deltapH with deltapsi occurs at low concentrations of weak bases and strong acids. High concentrations of weak bases and strong acids cause depression of deltamuH. 3. Concentrations of weak bases capable of abolishing deltapH, do not affect ATP synthesis. Concentrations of strong acids capable of abolishing deltapsi affect only slightly ATP synthesis. Concentrations of weak bases and strong acids capable of causing a decline of deltapH + deltapsi inhibit ATP synthesis. 4. Depression of deltamuH is paralleled by inhibition of ATP synthesis and decline of deltaGp, the phosphate potential. Abolition of ATP synthesis occurs only when deltamuH is below 20 mV. The deltaGp/deltamuH ratio increases hyperbolically with the decrease of deltamuH.
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PMID:Proton electrochemical gradient and phosphate potential in submitochondrial particles. 2 58

The influence of an anaesthetic dose of chlormethiazole (Hemineurin) on blood flow (CBF) and oxygen consumption (CMRO2) in the rat brain was investigated. In spontaneously breathing animals a dose of 160 mg . kg-1 of chlormethiazole, infused i.v., induced a state close to surgical anaesthesia. In paralyzed animals, the same dose decreased CBF and CMRO2 to about 60% of control, an effect similar to that observed after an anaesthetic dose of phenobarbitone. Neither a protective nor a detrimental effect of chlormethiazole could be demonstrated when the drug was given during reversible and pronounced, incomplete ischaemia, as evaluated from the postischaemic tissue concentrations of labile phosphates (PCr, ATP, ADP, AMP) and of lactate and pyruvate. It is concluded that protection in this situation (as earlier shown with phenobarbitone) must, at least partly, be related to other mechanisms than a depression of metabolism.
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PMID:Influence of chlormethiazole on cerebral blood flow and oxygen consumption in the rat, and its effect on the recovery of cortical energy metabolism after pronounced, incomplete ischaemia. 3 16

By determining glycogen synthetase activity, rate of 14C-glucose incorporation and glycogen levels, using pharmacologic agents which act on the alpha, beta M and N receptors, the influence of the autonomic system on synthesis of this polysaccharide in heart and skeletal muscle was analysed. The results indicate that the autonomic system is involved in intracellular autoregulation of glycogen synthetase activity through tissue receptors. Drugs which stimulate the cholinergic system depress this enzyme activity in the heart and skeletal muscle indirectly by releasing endogeneous catecholamines (nicotine-gangliconic effect) and also inhibit utilization of energetic ATP and phosphocreatinine reserves in the heart (muscarinic effect). Stimulation of the alpha-adrenergic receptor enhances glycogen anabolism in both types of muscles depending on the stimulatory influence of nonsterified sugers released in the process of glycogen hydrolysis and depression of cAMP level and presence of glucosteroids. Stimulation of beta-adrenergic receptors induces opposite changes. Analysis of the influence of pharmacologic agents that stimulate and inhibit decomposition and synthesis of glycogen showed that hydrolytic decomposition is probably one of the main processes of intracellular autoregulation of glycogen synthetase activity.
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PMID:The role of receptors of the autonomic system in regulation of glycogen synthetase activity in the heart and skeletal muscle in rats. 11 45

Like all inhalation anesthetics, halothane (CF3CHBrCl) has a dose-dependent negative inotropic effect on cardiac muscle. The mechanism of the action has not been determined, although effects on glycolysis, mitochondrial respiration and calcium kinetics, and sarcoplasmic reticulum ATPase activity have been suggested. Previous studies of the effect of halothane on the ATPase of contractile protein suffered from design and dosing defects. We have measured ATP splitting by canine cardiac natural actomyosin using extraction and equilibration procedures described previously (Honig, C. R. and Reddy, Y. C. 1973, J. Pharmacol. 184: 330-338). Drug dosing calculations were facilitated by measurement of the partition coefficient of halothane in protein. Halothane shifted the Ca++ concentration effect curve for actomyosin ATPase activity to the right. The maximum depression occurred at pCa 7.0 or 6.5. The effect was dose dependent with less than 10 percent depression at threshold and 50-60 percent depression at peak. Enzyme inhibition was antagonized by high Ca++ concentration, and was reversed by removing halothane from the reaction mixture. We suggest that inhibition of ATP utilization by the contractile system may be a mechanism of the in vivo myocardial depression produced by halothane.
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PMID:Halothane decreases actomyosin ATPase activity: a possible mechanism of the negative inotropic effect. 12 60

High doses of propranolol give rise to a liver disenzymic injury by depression of its clearance and colloidopexic functions, but without any histological change. The molecular target responsible for this disturbance seems to lie at the level of ATP-ase, because propranolol stimulates the membrane activity and supresses the citochondrial one. There are described some effects of this drug and its pharmocological opposite, isopropylenorepinephrine, on the liver cell enzymes, which may serve as a morphological proof of the antagonism between the mitochondrial and plasmalemal ATP-ase activity, on the one hand, and of the membrane ATP-ase and AMP-cyclase, on the other hand.
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PMID:Dynamic aspects of the liver ATP-ase and its functional involvement in propranolol treated rat. 12 89

The regulatory mechanism in the aortic actomyosin system was studied. Superprecipitation of desensitized aortic myosin B was not exhibited even in the presence of Ca2+, but was observable only in the presence of native tropomyosin and Ca2+. Reconstituted actomyosin composed of pure aortic myosin and pure skeletal actin did not show superprecipitation. Addition of aortic native tropomyosin and Ca2+ caused a marked superprecipitation. The ATPase of reconstituted actomyosin was enhanced three- or fourfold by aortic native tropomyosin and Ca2+. The extent of superprecipitation of aortic myosin B did not show a biphasic type of response to Mg-ATP concentration. Thus, aortic native tropomyosin induces a real activation of the myosin, actin, and ATP system in the presence of Ca2+, in contrast with the case of skeletal native tropomyosin, which induces the depression of skeletal myosin-actin-ATP interaction in the absence of Ca2+.
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PMID:Regulatory mechanism in arterial smooth muscle contraction. 14 28

The ATPase activity of chicken gizzard myosin was studied by varying the KCl concentration in the reaction medium. The following was thus found: (a) A sharp depression of the activity occurred when the KCl concentration was reduced to less than 0.3 M, showing the minimum activity around 0.15 M KCl. (b) The activity depression was removed by addition of urea or bay papain-digestion, but not by addition of p-chloromercuribenzoate. (c) In the KCl concentration where the activity depression occurred, the ATPase reaction proceeded in two distinct phases; the activity was relatively high in the early phase of the reaction and declined into the later phase where the steady state reaction took place. (d) In the KCl concentrations higher than that particular concentration or in the presence of urea, the ATPase reaction proceeded in one phase. (e) The temperature dependence of the ATPase activity in the early phase was of an ordinary magnitude being approximately equal to that of the ATPase activity in 0.6 M KCl. In contrast, the temperature dependence of the activity in the later phase was unusually small. Gizzard myosin in various concentrations of KCl was also examined by measuring the turbidity and the light-scattering intensity, and by observation under an electron microscope. The following was thus found: (a) In the KCl concentration where the activity depression occurred, there was a stagnation in the turbidity decrease as the KCl concentration was gradually increased and also the formation of "thick filaments," each of which was approximately 0.6-0.9 micron in length and 20-30 nm in diameter with no central "bare zone." (b) Addition of ATP induced dissociation of the thick filaments, and the dissociation occurred during the early phase of the ATPaseeaction. (c) Moreover, the temperature dependence of the ATP-induced dissociation rate was approximately equal to that of the ATPase activity in the early phase. On the basis of the findings mentioned above, it is concluded that the activity depression results from the ATP-induced dissociation of myosin filaments. Moreover, since high concentrations of KCl or urea also caused dissociation of myosin filaments and yet did not produce the activity depression, it was strongly suggested that gizzard myosin in the ATP-dissociated form must be different from that in the urea- or KCl-dissociated form, probably in the physical state of some myosin aggregates which were not detectable by the physical methods we used. As a side-observation, gizzard myosin filaments formed in the presence of ADP were found to be unusually long (longer than 2 micron), and they looked very similar to the particular filaments of skeletal myosin that were reported, by Moos, to be formed in the absence of the C protein.
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PMID:Adenosine triphosphatase activity and "thick filament" formation of chicken gizzard myosin in low salt media. 14 68

Earlier results on potassium ion inhibition of amino acid incorporation into the brain proteins in vivo (spreading cortical depression) led to the hypothesis that inhibition of protein synthesis is based on ATP deficiency. In the present study we tested various aspects of the aminocylation of tRNA, an ATP-dependent process, during spreading cortical depression produced by the topical application of 25% KCl. On using a 7-min interval between the subcutaneous injection of L-[U-14C] leucine and killing the rat, incorporation into the tRNA fraction was found to be reduced by 25%. Total amino acid radioactivity in the soluble fraction was unaltered. The acceptor capacity of tRNA, measured in vitro, and the proportion of non-acylated tRNA in vivo were likewise unchanged.
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PMID:On the mechanism of the inhibitory effect of potasium ions on amino acid incorporation into rat cerebral cortex proteins in vivo. 14 13

1. The oxidation of linoleate by rat-liver mitochondria has been studied as a function of substrate concentration. The oxidation of other long-chain unsaturated fatty acids shows similar characteristics. 2. At low concentrations, linoleate is readily oxidized in the absence of carnitine. Its rate of activation by the intramitochondrial acyl-CoA synthetase (EC 6.2.1.2) and subsequent oxidation is limited by the availability of intra-mitochondrial ATP. 3. A gradual increase of the linoleate concentration leads to (i) a strong depression of the rate of linoleate oxidation, and (ii) uncoupling of respiratory-chain phosphorylation together with induction of a mitochondrial ATPase activity. At still higher linoleate concentrations this ATPase activity is lowered rather than further stimulated and, concomitantly, the rate of linoleate oxidation increases again. 4. Evidence is presented that the inhibition by linoleate of the ATPase activity occurs at the level of the ATPase complex itself. This oligomycin-like effect of linoleate allows intramitochondrial linoleate activation to take place at the expense of ATP derived from substrate-level phosphorylation. 5. At very high concentrations of linoleate, its detergent action predominates and causes a complete inhibition of respiration as well as an extensive stimulation of an oligomycin-insensitive, Mg2+-dependent ATPase activity. 6. Measurement of the binding of radioactively labelled linoleate by isolated mitochondria shows that, at a given ratio of linoleate to mitochondrial protein, the ratio of bound to added linoleate is dependent on the concentration of the mitochondria.
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PMID:The oxidation of long-chain unsaturated fatty acids by isolated rat liver mitochondria as a function of substrate concentration. 15 Aug 57


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