Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sarcoplasmic and myofibrillar proteins of a frog mixed muscle (distal cruralis bundle) were investigated and compared to their fast twitch muscle homologues. Histochemical reactions revealed two populations of fibres in this muscle, differing from fast twitch fibres by the intensity of their myofibrillar ATPase reaction and by their mitochondrial NADH dehydrogenase activity. The distribution of parvalbumins and LDH isoenzymes in the whole muscle showed some features of tonic muscle type. Myosin light chains pattern of cruralis bundle fibres was characterized by the lower proportion of the LC3 subunit. These results confirmed the heterogeneity of this frog muscle and the presence of tonic or intermediate fibres with their typical sarcoplasmic and myofibrillar proteinic composition.
 ...
PMID:Comparison of the sarcoplasmic and myofibrillar proteins of twitch and tonic fibres of frog muscle (Rana esculenta). 644 68

The heart muscle is characterized by a high glycogen, lactic acid, lipid and fatty acids content and by high activities of phosphorylase , LDH, SDH, and GDH as an adaptation to its dynamic action of constantly pumping blood. The leg muscles behave as "fast muscles" and are characterized by having high myofibrillar. ATPase activity and relatively high activities of LDH, SDH and GDH as compared to the claw muscle which may explain their repetitive action during walking. The claw muscle is adapted to a tonic function as revealed by its low myofibrillar ATPase activity, high glycogen, high lipid and low values of LDH, SDH and GDH which further support its tonic action of short duration.
 ...
PMID:Studies on the metabolic differentiation of claw, leg and heart muscles of the fresh water field crab (Paratelphusa hydrodromus/Herbst/) 1. 645 57

Thyroidal trophic effects on slow-twitch skeletal muscle properties were compared in normally innervated and denervated soleus of rats maintained at different thyroid states. Hypothyroidism caused fast to slow changes in fiber type composition (99% decrease in proportion of type II fibers), ATPase activities (down 20-30%), myosin light chain pattern (54% less fast light chains), calcium uptake by SR (down 60%), LDH activity (down 11%), and isozyme pattern (9% decrease in M-subunits). Changes of similar magnitude but opposite in direction were induced by thyrotoxicosis. Denervations reversed, to varying degrees, the fast to slow transformations observed in hypothyroidism. However the slow to fast changes found in hyperthyroidism were facilitated rather than inhibited by denervation. These latter results clearly show that the hormone effect can be elicited in the absence of motor innervation. Furthermore, denervation alone caused slow to fast changes in euthyroid muscles. From these results, it is proposed that denervation and dysthyreosis alter muscle properties by independent mechanisms. Our data favor a direct action of thyroid hormone over a neurally mediated mechanism.
 ...
PMID:Evidence for a direct action of thyroid hormone in specifying muscle properties. 646 Dec 59

The human endosalpingeal ciliated cells are not a homogeneous cell population. They can be distinguished into mitochondria prominent and normal cells. The morphological appearance of ciliated cells was studied in organ culture using different hormones and hormone combinations in the culture media. Histological (HE, semithin sections) and histochemical methods (PAS, Alcian Blue, SDH, LDH, ATPase, 5'-Nucleotidase, acid and alkaline Phosphatase) were applied. Those mitochondria prominent ciliated cells which are seen in the native endosalpinx can in vitro also be determined mainly under the influence of steroid hormones (hydrocortisone and progesterone). In hormone free incubation media the apices of ciliated cells are separated. This will happen in hormone containing media, too, but with delay, however. Some results are in agreement with the possible transformation from ciliated cells to secretory cells.
 ...
PMID:[The histochemistry of human endosalpingeal ciliated cells (author's transl)]. 731 37

Damage to cell membrane system caused by methylmercury (Me-Hg) and its mechanism were studied with biochemical and cell biological methods experimentally. Results showed erythrocyte membrane and activities of T-ATPase, Mg(++)-ATPase and Na(+)-K(+)-ATPase of microsome membrane in brain, liver and kidney of the exposed animals decreased more significantly than of controls with a dose-effect pattern. Activities of Mg(++)-ATPase and Na(+)-K(+)-ATPase of erythrocyte membrane correlated positively with those of microsome membrane in brain and kidney. Sulfhydryl content of erythrocyte membrane and brain microsome membrane decreased significantly in the exposed animals (P < 0.01). Sulfhydryl content correlated inversely with the activities of above three kinds of ATPase in kidney, but so did in brain positively. Fluorescent polarization of membranes of erythrocytes and microsome in brain, liver and kidney increased, membrane fluidity decreased, LDH activities increased in plasma and decreased in cells and cell permeability increased in the exposed animals. Activities of respiratory enzymes of mitochondrion in exposed animals were lower than those in controls (P < 0.05). 3H-TdR incorporation was inhibited in spleen, liver and brain in exposed animals. Abilities of DNA synthesis and UDS repair were inhibited with high-dose of Me-Hg, and stimulated with low-dose. SCE frequency in bone marrow cells increased with dose of Me-Hg (P < 0.001). Proportion of splenocyte from G0/G1 to S phases increased and those from S to G2/M phases lowered, and it suggested DNA synthesis had been inhibited.
 ...
PMID:[Damage effects of methylmercury on cell membrane]. 760 Aug 93

Following experimental rhabdomyolysis, animals become resistant to heme protein-induced acute renal failure (ARF). The goals of this study were to: (a) ascertain whether this resistance, previously documented only in vivo, is expressed directly at the proximal tubular cell level; (b) determine whether heme proteinuria (vs. other consequences of rhabdomyolysis) is its trigger; and (c) ascertain some of its subcellular determinants. Rats were injected with a borderline toxic dose of glycerol and 24 hours later proximal tubular segments (PTS) were isolated for study. Their vulnerability to diverse forms of injury (FeSO4-induced oxidant stress, hypoxia, Ca2+ ionophore, cytochalasin D, PLA2) was compared to that found in normal PTS. Post-glycerol PTS manifested significant resistance to each insult (decreased lactate dehydrogenase +/- N-acetyl-beta-D-glucosaminidase release). Protection against FeSO4 was virtually complete and it was associated with a 50% decrease in membrane lipid peroxidation. No decrease in hydroxyl radical generation was noted during the FeSO4 challenge (salicylate trap assessment), suggesting a primary increase in membrane resistance to attack. That PLA2 addition caused less deacylation, plasma membrane enzyme (alanine aminopeptidase) release, and LDH leakage from post-glycerol versus normal tubules supported this hypothesis. To test whether cytoresistance was specifically triggered by heme proteins (vs. being a non-specific filtered protein effect, or a result of endotoxin cascade activation), rats were injected with purified myoglobin, non-heme containing filterable proteins, or endotoxin. Only myoglobin induced cytoresistance. In vivo heme oxygenase inhibition (tin-protoporphyrin) did not block the emergence of cytoresistance and it was expressed despite Na,K-ATPase inhibition (ouabain) or cytoskeletal disruption (cytochalasin D). In vivo heat shock failed to protect. In conclusion, (1) rhabdomyolysis induces broad based proximal tubular cytoresistance; (2) heme proteinuria is its trigger; and (3) it is most easily explained by a primary increase in plasma membrane resistance to attack.
 ...
PMID:Heme protein-induced tubular cytoresistance: expression at the plasma membrane level. 763 63

Cationic antiseptics--catamine AB, polysept (polymeric derivative of chlorhexidine) as well as cationic protein protamine exhibited a pronounced cytotoxic effect on human skin and lung fibroblasts in cell culture. Their effect was accompanied by augmentation of lipid peroxidation products and by inhibition of DT-diaphorase, LDH, ATPase and glutathione reductase. Introduction of alpha-tocopherol into the cultural medium normalized the rate of lipid peroxidation but did not remove the inhibitory effect on activity of oxidoreductase studied. Blood serum proteins immunoglobulins and albumin diminished significantly the cytotoxic effect of cationic preparations contributing to restoration of all the parameters studied to control values; this phenomenon appears to occur due to nonspecific membrane protective and antioxidation effects of the blood serum proteins.
 ...
PMID:[Some biochemical indicators of the cytotoxic response of human fibroblasts cultured with natural and synthetic polycations]. 779 94

The effect of oral treatment with sennosides (50 mg/kg) on the time-course of net H2O and electrolyte transport rates was studied in 1-hour incubation experiments in the rat colon in vivo. Net H2O, Na+ and Cl- absorption rates did not change during the first 4 h after treatment, but were reversed to net secretion after 6 h and partly recovered during the next 18 h. K+ and Ca2+ were secreted in controls, and net secretion increased from 6 to 24 h after treatment. Paracellular permeability of [14C]erythritol was 3-fold 6 h after treatment but unchanged at other times after treatment (2, 4, 12 or 24 h). LDH leakage into the lumen was not enhanced by treatment. Neither mucosal Na+, K(+)-ATPase activity nor cAMP or phosphodiesterase activity was affected by sennosides. As stool consistency and acceleration of transit by sennosides has entirely normalized 24 h after treatment but not net absorption of H2O and electrolytes, it is concluded that there may be regional differences in the absorptive behavior of the colon induced by sennosides. Slow transit and increased absorption in some parts of the colon may overcome secretion in other parts.
 ...
PMID:Sennoside-induced secretion and its relevance for the laxative effect. 823 22

Some polychlorinated biphenyls (PCBs) have been reported to alter locomotor activity and decrease brain dopamine function in laboratory animals. PCBs with ortho- and/or parachlorine substitutions and varying number of chlorinations are known to decrease cell dopamine content in vitro and have been detected in brains of animals exposed to PCBs, suggesting that the neurotoxicity could be mediated by ortho-substituted congeners. Dopamine or other neurotransmitter uptake and release phenomena are dependent on the maintenance of intracellular Ca2+ homeostasis, and perturbations in Ca2+ homeostasis could lead to altered cell function and/or death. We compared the effects of two PCB congeners on Ca2+ homeostasis in cerebellar granule cells: 2,2'-dichlorobiphenyl (DCBP), a putative neurotoxic congener, and 3,3',4,4',5-pentachlorobiphenyl (PCBP), a presumed nonneurotoxic congener. In cerebellar granule cells (6-8 days in vitro), DCBP was cytotoxic as indicated by a significant increase in LDH leakage at 200 microM after 2 hr of exposure and at 100 microM after 4 hr exposure. PCBP, on the other hand, did not affect LDH leakage even at 200 microM for up to 4 hr. Although both congeners increased cerebellar granule cell [Ca2+]i, DCPB was more effective in increasing [Ca2+]i to a greater extent than PCBP. The increase in [Ca2+]i produced by both congeners was not transient, but a steady rise was observed with time. To understand cellular Ca(2+)-buffering capacity, Ca2+ sequestration and Ca2+ extrusion were studied in mitochondria, microsomes, and synaptosomes, isolated from adult rat cerebellum. DCBP was a potent inhibitor of 45Ca2+ uptake by mitochondria (IC50 = 6.17 +/- 0.53 microM) and microsomes (IC50 = 7.61 +/- 0.35 microM). PCBP inhibited Ca2+ sequestration by mitochondria (68% of control) and microsomes (72% of control), but the effects were much less than those produced by equivalent concentrations of DCBP. Synaptosomal Ca(2+)-ATPase was inhibited by DCBP, but not by PCBP. These results indicate that at concentrations where cytotoxicity in cerebellar granule cells was not observed, DCBP increased intracellular [Ca2+]i, and at the same concentrations, Ca2+ sequestration by intracellular organelles and Ca(2+)-ATPase in synaptic plasma membrane were inhibited. Although PCBP increased [Ca2+]i in cerebellar granule cells to some extent, it was not potent in affecting Ca2+ sequestration or Ca2+ extrusion in adult cerebellar components. Hence, PCBP-induced slight increase of [Ca2+]i levels in the cells might have been associated with effective Ca2+ sequestration by intracellular organelles, as seen in cerebellar preparations. The results of this study support the hypothesis that the position of chlorine substitution on the biphenyl ring and/or number of chlorine substitutions may have significant implications for predicting potential effects of PCB congeners in the nervous system, and perturbations in Ca2+ homeostasis might play a significant role in the neuroactivity of PCBs.
 ...
PMID:Comparative effects of two polychlorinated biphenyl congeners on calcium homeostasis in rat cerebellar granule cells. 823 68

The effects of amiodarone on mitochondrial ATPase (EC 3.6.1.3) and lactate dehydrogenase (LDH: EC 1.1.1.27) activities were studied in guinea pig mitochondrial preparations in order to test the hypothesis that amiodarone exerts some of its effects as a result of multiple actions on membrane-bound enzymes and receptors. Amiodarone inhibited the ATPase activity in the range of 10 pM to 10 mM (n = 10) with IC50 values of 56.4 +/- 7.2 microM. However, although the inhibitory action was very significant (P < 0.0001, compared to the control) in the concentration range of 100 pM to 10 microM, the differences in individual enzyme responses showed very weak correlation with drug concentration. In this region, the inhibitory effects were almost constant at approximately 37%. Below 100 pM and above this range however, the concentration-response relationships were steep, reaching total inhibition at approximately 2.5 mM. Amiodarone also exerted concentration-dependent inhibitory effects on lactate dehydrogenase activity. However, over the effective inhibitory concentration range (5-95%) of 7.5 microM to 2.5 mM (n = 8) and IC50 value of 108 +/- 6 microM, its inhibitory potency was twofold weaker than that of its ATPase inhibition. We propose that these actions contribute, at least in part, to the mechanism(s) of some of the pharmacological actions of amiodarone.
 ...
PMID:Actions of amiodarone on mitochondrial ATPase and lactate dehydrogenase activities in guinea pig heart preparations. 825 7


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>