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)

Studies were conducted into the activities of calcium, magnesium, and sodium-potassium ATPase as well as into crude protein levels in homogenate and cell fractions of brain of two foetuses, aged 111 days, and of two piglets each, aged two days or nine weeks. The average brain-borne crude protein percentages were 6.55 in the foetuses, 7.25 in the two-day piglets, and 9.60 in the nine-week piglets. Calcium, magnesium, and sodium-potassium ATPase activities, related to one gram of fresh brain mass, were found to go up along with growing age. Highest relative percentages of sodium-potassium ATPase were recordable from homogenate and from the mitochondrial and microsomal fractions of the foetuses. Certain quantitative differences were obtained from using calcium, magnesium, sodium, and potassium ions to stimulate ATPase in the fractions of cell nuclei, mitochondria, and microsomes. The optimum temperature for magnesium and sodium-potassium ATPase in homogenate and in the mitochondrial fraction of brain was 45 degrees C.
 ...
PMID:[Studies of the presence of enzymes in various tissues of swine. 4. Studies of the Ca-, Mg-, and Na-K-ATPase activities in the homogenate and cell fractions of brain of fetuses and piglets]. 23 97

This paper describes the acute effects produced by administering potassium (2.7 and 5.5 mg.per kg of weight) to rabbits intoxicated with 10 and 30 mg.kg-1 of thallium. Acute capture (90 minutes) of thallium by skeletal muscle, left ventricle, liver and renal medulla and cortex is studied. Different doses of thallium were found to modify the organic capture in the studied organs with quantitative differences. The administering of potassium also modified the magnitude of capture, in different magnitudes, in the various organs. The modification produced depends more upon the studied organ than on the dose of potassium given. The skeletal muscle seems to manage the thallium-potassium interaction depending on the activation of sodium-potassium ATPase. The liver does not seem to be directly affected by the thallium-potassium interaction. The left ventricle captures thallium very rapidly, and also seems to depend on the activation of sodium potassium ATPase, and potassium increases thallium capture. The renal medulla captures 4 to 5 times more thallium than its cortex and the high dose of thallium seems to saturate the medulla's capture. The renal cortex's capture was not renal elimination of thallium is activated by potassium. The renal cortex uptake was not modified by potassium but the renal thallium elimination seems to be activated by potassium. The uptake by the renal medulla is diminished by potassium, suggesting a thallium-potassium interaction similar to the competitive inhibition described by McCall et al. (1985).
 ...
PMID:[Acute effects of the administration of potassium on the organ uptake of Tl+ in the rabbit]. 213 77

Changes of the intracellular Ca concentrations play a predominant though not unique role in the regulation of the force development of smooth muscle cells. Contraction is initiated by an influx of Ca2+ through the cell membrane or by the release of Ca2+ from intracellular storage sites. Ca influx occurs via voltage operated channels and receptor operated channels. The intracellular Ca release induced by agonists probably originates from the endoplasmic reticulum. The removal of Ca2+ from the cytoplasm occurs by extrusion across the plasmalemma and by reaccumulation in the endoplasmic reticulum. These active Ca2+ transport systems are catalysed by (Ca2+ +Mg2+) ATPases. Na-Ca exchange across the sarcolemma of smooth muscle is probably of minor importance since the (Ca2+ +Mg2+)ATPase activity of plasma membranes is higher than the activity of the Na+K+ ATPase, the ultimate energy source for Na+-dependent Ca2+ extrusion. The (Ca2+ +Mg2+)ATPase of the plasmalemma has a Mr of 130.000 and it is stimulated by calmodulin. It resembles the Ca2+ transport ATPase of erythrocyte membranes, including immunological cross-reactivity. The Ca2+ transport enzyme of the endoplasmic reticulum has a Mr of 100.000, is insensitive to calmodulin and resembles the Ca2+ pump of sarcoplasmic reticulum of skeletal muscle. However, antibodies against the Ca2+ pump of skeletal muscle do not cross react with the enzyme of smooth muscle. Subcellular fractionation of pig stomach smooth muscle indicates that in this tissue the large fraction of the (Ca2+ +Mg2+)ATPase activity is present in the plasma membrane while less activity is found in the endoplasmic reticulum.
 ...
PMID:Regulatory systems for the cytoplasmic calcium concentration in smooth muscle. 242 11

As cells grown in tissue culture age, they typically become altered when compared to their in vivo counterparts. Bovine corneal endothelial cells were grown in culture for periods up to 60 days (primary = 10 days; secondary = 50 days). The plasma membrane enzymes: Na+K+ ATPase and Mg2+ ATPase were assayed for specific activity at selected intervals throughout the growth periods. In primary cultures, it was found that Na+K+ ATPase was quite low at 5 days (0.05 units), but increased fourfold at 10 days (0.22 units). By contrast, Mg2+ ATPase changed little over the same period. Tissue cultures grown secondarily had Na+K+ ATPase activity fall 0.3 units (0.52 to 0.22) for 35 days after a single trypsinization. After five trypsinizations over a 50-day period, the activity fell 0.23 units (0.33 to 0.10). The alterations in Mg2+ ATPase activity were more complex in secondary cultures. In the instance in which a single trypsinization was used, the activity fell 0.15 units at day 20, rose 0.12 units (above the starting value) at day 25, then returned to the initial level by day 35. When multiple trypsinizations were used, the activity fell 0.06 units by day 30, then remained stable for the duration. The data may be indicative of mechanisms such as receptor alteration, feedback inhibition and genetic instability when these cells are grown in culture.
 ...
PMID:Age as a function of ATPase activity in cultured corneal endothelial cells. 253 48

In vitro effects of aspirin and paracetamol at the doses 200, 400, 600, 800 nmole/mg protein on ATPases activity were studied in the cerebrum and cerebellum of human fetus covering the age range from 10 weeks to 32 weeks of gestation. Both aspirin and paracetamol inhibit Na+K+ ATPase and Mg2+ ATPase in a dose dependent manner. The inhibition of Na+K+ ATPase and Mg2+ ATPase activity which may affect the release and uptake of biogenic amines in CNS, hinders the maturation of human fetal brain.
 ...
PMID:Effects of aspirin and paracetamol on ATPases of human fetal brain: an in vitro study. 256 Nov 17

An experimental trial was conducted to study the effects of phenoxybenzamine, cocaine, carbamazepine, loxapine, clozapine, clothiapine, thiothixene, droperidol, alprazolam, imipramine, maprotiline, dibenzepin, nomifensine, trazodone, mianserin, viloxazine, doxepin and amoxapine on photocolorimetrically rated ATPase activity and on related oxygen uptake, determined by manometrical means, within a concentration range of 0.1-0.001 mM. Phenoxybenzamine, clothiapine and maprotiline at 0.1 mM inhibited sodium-potassium ATPase activity and related QO2 by 30-40%. Loxapine, trazodone, amoxapine and alprazolam at 0.1 mM inhibited sodium-potassium ATPase activity by 25-35%. Imipramine, nomifensine and droperidol at 0.1 mM inhibited QO2 by 20-35%. Cocaine, at all concentrations assayed, inhibited ouabain insensitive ATPase. The remaining drugs did not produce significant modifications.
 ...
PMID:Effects of several neuroleptics, antidepressants and monoamine uptake blockers on ATPase activity and related oxygen uptake in rat brain in vitro. 257 98

Membrane-rich vesicle preparations of rabbit and bovine lenses were prepared in such a manner as to preserve ATPase activity. The lipid:protein ratio of these preparations was increased 22- to 33-fold with a 94% recovery of total phospholipid. Using this preparation, calcium stimulated ATPase was routinely determined in both individual lenses and in pooled specimens. The pattern of stimulation of ATPase activity by a range of calcium concentrations was found to be similar in membrane preparations of epithelium and cortex, from rabbit and bovine lenses. The concentration of calcium necessary for half-maximal stimulation of ATPase activity was approximately 10(-6) M. Calcium concentrations in excess of 10(-4) M reduced the ATPase activity. Calcium-ATPase was undetectable in the lens nuclear region of both species. The regional distribution of sodium-potassium ATPase was also measured.
 ...
PMID:Ca-ATPase activity in the rabbit and bovine lens. 283 34

We investigated the response of mitochondrial function and microsomal adenosine triphosphatase (ATPase) activity in rat liver tissue subjected to in vitro ischemia at either 0 degree C to 4 degrees C or 37 degrees C for 30 to 60 minutes. Mitochondrial coupling, expressed as respiratory control index, was preserved at up to 60 minutes' cold ischemia. However, respiratory control index was decreased significantly from control by 30 minutes of warm ischemia. Both microsomal magnesium-activated ATPase and sodium-potassium ATPase activity were significantly increased by 60 minutes of warm ischemia yet were unaltered by 60 minutes of ischemia at 0 degree C to 4 degrees C. Warm ischemia produces deleterious effects on energy-generating (mitochondria) and energy-utilizing (ATPase) activity. Hypothermia provides a significant prolongation of cellular viability in ischemic tissue in terms of bioenergetic status. In addition to organ procurement and transplantation, hypothermic cytoprotection may prove valuable in areas such as shock, ischemia, and other clinical conditions of compromised visceral perfusion.
 ...
PMID:Hepatic microsomal adenosine triphosphatase and mitochondrial function. Response to cold and warm ischemia. 295 19

We measured the effects of ouabain on sodium-potassium ATPase (Na-K ATPase) specific activity (SA) and rubidium (Rb) transport in newborn (NB) and adult (Ad) sheep myocardium (myo), guinea pig myo and red blood cells (RBC), and human RBC. 50% inhibition of Na-K ATPase SA and Rb transport occurred at ouabain concentrations between 10(-4.8) and 10(-7.6) M in different species; within a species, 50% inhibition of Rb transport occurred at lower ouabain concentrations than 50% inhibition of Na-K ATPase SA. No differences between mature and immature tissues were found. Ouabain binding stability to Na-K ATPase extracted from myo and RBC did not vary with age. Binding studies revealed a KD X 10(-8) M of 0.87 +/- 0.09 for NB human RBC and 0.88 +/- 0.14 for Ad human RBC. Calculated RBC receptor density however, was higher in the Ad (1.25 +/- 0.08 sites/micron2) than in the NB (1.03 +/- 0.04 sites/micron2, p less than 0.01). Binding studies in extracted myocardial specimens showed a KD X 10(-8) M of 1.23 +/- 0.27 for NB and 1.09 +/- 0.46 for Ad; mM ouabain bound X 10(-12)/Na-K ATPase unit were 355 +/- 120 (SEM) for NB and 316 +/- 51 for Ad. These studies of cardiac glycosides reveal few age-related differences in drug binding or inhibition of monovalent cation transport.
 ...
PMID:Effects of ouabain on monovalent cation transport in mammalian tissue. 300 50

The quantitative relationship between fractional myocardial thallium uptake and radioactive microsphere-determined flow was studied in 33 open chest dogs under baseline conditions during increased coronary flow (dipyridamole), decreased coronary flow (propranolol and coronary artery stenosis), inhibition of Na-K ATPase (ouabain), and regional infarction. Myocardial contents of thallium and microspheres were compared in left ventricular (LV) biopsies taken 5, 10, 15, 30, and 60 min after thallium injection, expressed as fractions of injected dose. Maximal LV thallium uptake occurred 10 min after injection and the 10-min values were therefore used for subsequent comparisons. Combining all dogs, fractional LV thallium content (% injected dose) correlated well with fractional LV blood flow (% cardiac output) (r = 0.95). However, for fractional LV flows in the low, normal, or moderately elevated range (LV flow/cardiac output less than 9%), thallium content consistently exceeded flow by about 15%. This relationship was not altered by ouabain or regional ischemia or infarction. For greatly elevated fractional LV flows (greater than 9%), thallium content was not significantly different from flow. To explain these differences, myocardial and systemic extraction fractions for thallium were determined in eight dogs with a dual tracer method. At baseline, myocardial extraction fraction was significantly greater than systemic (88 +/- 0.4% compared with 75 +/- 1%, p less than 0.001). During dipyridamole, myocardial extraction fraction decreased and myocardial and systemic values were no longer significantly different (82 +/- 1% compared with 79 +/- 1%). These results show that the fraction of injected thallium dose taken up by the LV myocardium exceeds the delivered fraction of cardiac output over a wide range of LV flows, and is not altered by ouabain-induced inhibition of sodium-potassium ATPase or regional myocardial infarction. This difference is explained by a greater myocardial than systemic extraction fraction for thallium. During high LV flows produced by dipyridamole, fractional LV thallium uptake and flow become similar as myocardial and systemic extraction fractions equalize.
 ...
PMID:Quantitative relationship between global left ventricular thallium uptake and blood flow: effects of propranolol, ouabain, dipyridamole, and coronary artery occlusion. 301 29


1 2 3 4 5 6 7 Next >>