Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Trimethaphan, a ganglionic blocking agent which is administered by intravenous drip to produce controlled hypotension during surgery, produces a complete neuromuscular blockade at the isolated phrenic nerve-hemidiaphragm preparation of the rat at a concentration of 0.3 mmol X l-1. This blockade is not reversed by neostigmine, a cholinesterase inhibitor, nor by calcium chloride, and this action is attributed to the local anaesthetic activity of the drug. Trimethaphan (1.5 X 10(-2) mmol X l-1) interacts with the following aminoglycoside antibiotics: gentamicin (0.04), streptomycin (0.05), netilmicin (0.06), amikacin (0.11), sisomicin (0.14), kanamycin (0.17), tobramycin (0.18) and dibekacin (0.21 mmol X l-1) to produce a complete neuromuscular blockade. These pharmacodynamic interactions of trimethaphan and aminoglycoside antibiotics occur at significantly reduced concentrations of the interacting drugs which are very close to the ones obtained after administration of therapeutic doses. When trimethaphan or aminoglycoside antibiotics are used alone at the above reduced concentrations they do not exert any neuromuscular blocking activity. The neuromuscular blockade which is obtained after the interaction of trimethaphan with aminoglycoside antibiotics is not reversed by either neostigmine or calcium chloride, although the neuromuscular blockade which is produced by aminoglycoside antibiotics alone is reversed by calcium chloride. It is concluded that the local anaesthetic effect of trimethaphan is the predominant factor of the mechanism of the above interactions. These interactions may produce severe respiratory disturbances (respiratory depression or apnoea) to the patients, during the perioperative period, which can be reversed only with artificial ventilation.
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PMID:Aminoglycoside antibiotics: interaction with trimethaphan at the neuromuscular junctions. 362 53

The hypothesis that the toxic effects of imidocarb mediated by reduced cholinesterase activity might be intensified by hypomagnesaemia was tested in calves. Hypomagnesaemia was induced in 12 males (50 kg) using an artificial milk based on a commercial nondairy coffee creamer. Although plasma magnesium levels reached 0.33 mmol litre-1 in two weeks no clinical signs were detected. In 12 control calves a daily magnesium supplement of 0.6 g was inadequate although the published requirement is 0.45 g; it was raised to 1.2 g to keep plasma magnesium normal. Lighter calves developed hypomagnesaemia more readily and fast-growing calves had lower plasma urea concentrations. Plasma calcium, but not plasma magnesium, showed significant positive correlation with plasma albumin. The only statistically significant effects of hypomagnesaemia were slight elevations of white cell count and plasma sodium. The hypomagnesaemic and normomagnesaemic calves were divided into two equal groups and treated with 3.3 mg kg-1 of imidocarb dipropionate or a placebo. The drug produced the expected clinical signs of mild toxicity and depression of cholinesterase but no other adverse effects. Transient slight depressions of plasma calcium and potassium concentration, a transient rise of plasma sodium and elevation of creatine kinase occurred. None of the effects of imidocarb treatment was intensified by hypomagnesaemia except, perhaps, constriction of the pupils; generally, hypomagnesaemic animals were affected less.
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PMID:Effect of induced hypomagnesaemia on the toxicity of imidocarb in calves. 370 46

In Krebs solution (3.36 mM Ca2+), the maximal contractile response of human ileal and urinary bladder detrusor muscle to acetylcholine (ACh) was 40-60% that to carbachol (CCh). The maximum response to ACh was reached at a bath concentration of about 1 microM and was maintained throughout a range extending to 100 microM. In the presence of neostigmine (0.1 microM), the maximum response to ACh reached the level of that of CCh. However, bioassay of bath concentrations of ACh at various points of the maximal response in the absence of neostigmine revealed only slight to insignificant diminution of the applied concentration of ACh. Joint application of ACh and CCh generated a dose-response profile consistent with a model of competitive antagonism between a full agonist (CCh) and a partial one (ACh). Also, choline (100 microM) reduced the maximum response to ACh in the presence of neostigmine and that to CCh to 60-80% of control. These observations are consistent with a mechanism whereby intact cholinesterase together with its substrate ACh and possibly a breakdown product of ACh constitute a filter or diffusional barrier regulating the flow of agonist from the enzyme compartment to the receptor compartment.
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PMID:A study of the contractile response to acetylcholine in human ileal and detrusor muscle: origin of the low efficacy of acetylcholine. 370 60

Using fully mechanized analytical equipment, interference by haemolysis in the determination of 26 clinical chemical parameters was determined quantitatively by adding haemolysate to serum. Haemoglobin concentrations up to 6.6 g/l caused essentially no interference in the following determinations: albumin (immuno-nephelometric), alpha-amylase, calcium, chloride, cholesterol, cholinesterase, creatinine, iron, glucose, glutamate dehydrogenase, uric acid, urea, sodium, inorganic phosphate, total protein, transferrin and triglycerides. In the presence of haemoglobin, erroneously high values were found for: lactate dehydrogenase (haemoglobin higher than 0.2 g/l), aspartate aminotransferase, potassium and acid phosphate (haemoglobin higher than 1.5 g/l), creatine kinase (haemoglobin higher than 2.5 g/l) and alanine aminotransferase (haemoglobin higher than 3.4 g/l). Erroneously low values were found for bilirubin (haemoglobin higher than 0.8 g/l), alkaline phosphatase and albumin (by electrophoresis) (haemoglobin higher than 1.5 g/l) and gamma-glutamyltransferase (haemoglobin higher than 3.0 g/l).
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PMID:Haemolysis as an interference factor in clinical chemistry. 371 97

The resting efflux of choline from perfused chicken hearts varied from 0.4 to 2.6 nmol/g min, but was constant for at least 80 min in the individual experiments. The rate of choline efflux was found to be equal to the rate of choline formation in the heart, which, from the following reasons, was essentially due to hydrolysis of choline phospholipids. Cardiac content of choline phospholipids (7,200 nmol/g) was much higher than that of acetylcholine (5.5 nmol/g). Resting release of acetylcholine was 0.016 nmol/g min and, after inhibition of cholinesterase, only about 0.1 nmol/g min. Resting efflux of choline was reduced by mepacrine, a phospholipase A2 inhibitor, by perfusion with a Ca2+-free Tyrode's solution containing EGTA and by the combination mepacrine plus Ca2+-free/EGTA solution. In all experiments the reduced choline efflux levelled off within 10 min at about 50%. Omission or elevation of Mg2+ from 1.05 to 10.5 mmol/l had no effect. Resting efflux was increased to 150% by oleic acid (as sodium salt; 2 X 10(-5) mol/l) which is known to activate phospholipase D. Likewise muscarinic agonists (carbachol and acetylcholine) caused facilitation of the efflux of endogenous choline that was blocked by 3 X 10(-7) mol/l atropine. This effect was not reduced, but even slightly enhanced, by mepacrine and by infusion of EGTA in a modified Tyrode's solution (Ca2+-free, 10.5 mmol/l Mg2+). It is concluded that the resting efflux of choline from the heart is essentially due to hydrolysis of choline phospholipids, that half of the efflux is insensitive to mepacrine and is Ca2+-independent (excluding an involvement of phospholipase A2).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of choline efflux from the perfused heart at rest and after muscarine receptor activation. 371 69

Clinical chemistry reference values in blood from 48 nonfasting Chester White/Yorkshire and 48 Hanford Miniature swine were determined. Subsequently, 40 animals of each breed were restrained in a cloth sling and fasted for 24 hours while exposed percutaneously to pinacolyl methylphosphonofluoridate (soman). The range of dosages for the Hanford Miniature swine was 2.0 to 15.8 mg/kg, and for the Chester White/Yorkshire swine, the range was 4.0 to 25.0 mg/kg. Sham-exposed groups, consisting of 8 animals of each breed, were treated in an identical manner, except no anticholinesterase agent was administered. Samples of blood were drawn at 1, 7, 14, and 28 days after soman or sham exposure. In the sham-exposed groups, significant changes from the reference values were observed as a result of the 24-hour restraint. In both breeds, skeletal muscle enzyme activities were increased, plasma cholinesterase activity (ChEPL) was decreased, calcium concentration was decreased, and phosphorus concentration was increased. Percutaneous exposure to soman resulted in decreases of ChEPL and erythrocyte cholinesterase activities (ChERBC). The ChEPL recovered more quickly than the ChERBC in both breeds. Even in asymptomatic swine, the decrease of ChERBC was greater than 60% after 24 hours. In the swine of each breed given the largest dosage, hyperglycemia was apparent in blood samples taken at the onset of apnea, especially when the animal survived for greater than 2 hours. We conclude that both breeds of swine, on the basis of dispersion in clinical chemistry reference values, were equally suited for this type of dermatotoxicity study. The sling method of restraint, however, caused some undesirable changes in biochemical values.
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PMID:Clinical chemistry reference values in two breeds of swine and their changes during percutaneous exposure to soman. 382 68

The possible role of nerve activity in triggering changes in the localization of acetylcholine receptors (AChRs) and cholinesterase (ChE) on nerve-contacted Xenopus muscle cells has been assessed. The localization of these molecules was examined on nerve-contacted and noncontacted muscle cells in cultures of spinal cord and myotomal muscle derived from Xenopus embryos. Sites of high AChR density were revealed by staining with fluorescent alpha-bungarotoxin and sites of ChE localization were revealed histochemically. Localization of AChRs and ChE at sites of nerve-muscle contact occurred when the culture medium contained 1.2 micron tetrodotoxin (TTX), 1.2 micron TTX, 10 mM magnesium, and no calcium salts, 1.2 micron TTX and 2 mM manganese, or 106 mM potassium methyl sulfate instead of sodium chloride. The nerve-contacted muscle cells in each of these modified culture media also exhibited a reduced incidence of AChR and ChE patches away from the site of contact. It is concluded that the neural factor(s) that triggers the local and remote changes in AChR and ChE distribution can be supplied to the neurites and externalized in the absence of nerve impulses, and that the nerve and muscle cells can interact even when they are largely depolarized.
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PMID:Localization of acetylcholine receptors and cholinesterase on nerve-contacted and noncontacted muscle cells grown in the presence of agents that block action potentials. 395 89

The effect of hypoparathyroidism and low blood calcium on enzyme levels in rat liver and kidney is shown. Four animal groups were used: parathyroidectomized (PTX), PTX with CaCl2 added in the drinking water, sham-operated controls and sham-operated with CaCl2 added in the drinking water. PTX significantly lowered serum parathyroid hormone (PTH) and calcium. Supplementation of CaCl2 in the drinking water increased serum Ca levels in PTX rats but not in the controls. Significant changes in several liver and kidney enzymes were seen. Most affected were the liver NADP dependent enzymes, glucose-6-phosphate dehydrogenase and malic enzyme. Similar patterns but with relatively smaller changes were seen in the liver enzymes, lactic dehydrogenase, hexokinase, and aspartate transferase. No significant differences between the groups were seen in the levels of malic dehydrogenase, isocitric dehydrogenase, fructose-6-phosphate kinase and cholinesterase. In the kidney, which was less affected than the liver, the only significant difference was seen in the level of malic enzyme. Serum total lipids in the PTX group were significantly lower. All the changes seen were partially reversed by Ca supplementation in the drinking water.
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PMID:Biochemical change in the liver and kidney of rats following parathyroidectomy. 400 1

Eight hematologic parameter values, 16 serum biochemical constituents, serum protein fractions and albumin-globulin ratios were determined in blood samples obtained from 879 normal, healthy Beagle dogs of both sexes which had been reproduced and bred in our laboratories. The blood samples were collected from the Beagles that ranged in monthly ages from 1 to 12 and in monthly ages from 13 to 121, which were classified as the adult class. As a result, red blood cell counts, hemoglobin concentrations and packed cell volumes increased with growth. Red blood cell parameters of normal Beagles in our laboratories were rather higher than those in literatures presented by many other researchers. MCV decreased and MCHC increased gradually with age. Total serum protein concentrations increased with growth. alpha 1-1 and alpha 1-2 Globulin fractions descended, but beta 2 and gamma globulin fractions ascended in serum proteins. Alkaline phosphatase activities, inorganic phosphorus concentrations and glucose concentrations decreased conspicuously with growth. Leucine aminopeptidase activities and calcium concentrations decreased slightly. Serum cholinesterase and LDH activities showed a tendency to diminish similarly. Blood urea nitrogen and creatinine concentrations multiplied gradually. Hematologic parameters became almost steady in our 7-month-old dogs or older ones and serum biochemical constituents had a tendency to be stable in our 7- to 9-month-old dogs or older ones in the blood. White blood cell counts, alkaline phosphatase activities, inorganic phosphorus concentrations, glucose concentrations, leucine aminopeptidase activities and calcium concentrations were lowest in the adult class.
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PMID:[Successive changes in the blood composition of experimental normal beagle dogs associated with age]. 408 64

1. End-plate potentials were recorded intracellularly at the frog neuromuscular junction bathed in a solution containing a low concentration of calcium and a high concentration of magnesium.2. The muscle was subsequently subjected to ;cholinesterase staining', and the area of the individual end-plates, studied with intracellular electrodes, was measured.3. A positive correlation was found between the end-plate area and the diameter of muscle fibres.4. The mean quantum content (m) showed a positive correlation with the size of end-plates.5. The frequency of spontaneous miniature end-plate potentials was positively correlated with m as well as with end-plate area.6. It is concluded that the amount of transmitter released following nerve stimulation is related to the size of nerve endings.
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PMID:Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog. 432 33


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