Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The topography of the activity of succinate dehydrogenase, cytochrome oxidase, monoaminoxidase and esterase was studied in the arc of the aorta of the monkey, dog, cat, rabbit, rat. It was established that terminal portions of baroreceptors were accumulators of the activity of enzymes of the succinoxidase system connected with the mitochondria of a nervous component of sensory endings and the activity of cholinesterase localized in the zone of terminal branches of the baroreceptors fibres in the underlying specialized tissue. The activity of monoaminoxidase was found in the cytoplasm of Schwann cells of the baroreceptor fibres. No specific esterase was revealed in the baroceptors of the aorta arc of the animals in question. The enzymic organization of the cat's aorta baroreceptors is different from that of the other animals.
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PMID:[Enzymochemical organization of aortic baroreceptors]. 17 5

The distributions of acid and alkaline phosphatases, 5-nucleotidase, ATPase, non-specific esterase, specific cholinesterase, succinic dehydrogenase and beta-galactosidase are described in the mesencephalic auditory, tegmental and cranial nerve nuclei of the frog (Rana tigrina). The main results of the study are as follows: The laminar, principal, and magnocellular nuclei of the torus semicircularis, which are associated with auditory functions, show intense activity of specific cholinesterase. On the other hand, the commissural and subependymal mid-line nuclei, whose functions are doubtful, show a complete lack of this enzyme. The nucleus isthmi shows intense acid phosphatase, ATPase, non-specific esterase, specific cholinesterase and succinic dehydrogenase activities. Non-specific esterase is virtually absent from all the areas studied except the nucleus isthmi and the 3rd and 4th cranial nerve nuclei. Most of the commissures and fibre tracts show intense activity for beta-galactosidase and 5-nucleotidase. The possible roles of these enzymes in glycolipid and myelin metabolism are discussed.
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PMID:Histoenzymological analysis of mesencephalic auditory, tegmental and cranial nerve nuclei in the frog (Rana tigrina). 21 17

Two kinetic models are introduced which predict amplitudes and time-courses of endplate currents and miniature endplate currents at neuromuscular junctions, at both normal and acetylcholinesterase-inhibited endplates. Appropriate differential rate equations reflecting interactions of acetylcholine with acetylcholine receptor and with esterase, diffusion of acetylcholine both within and from the synaptic cleft, and cooperativity between receptor site occupancy and ion channel opening are solved. Acetylcholine release into the cleft is assumed to be instantaneous. The simpler homogeneous reaction space model accurately predicts decay phase time constants are inaccurate. The two-reaction space model predicts amplitudes and time constants within a factor of two of those observed experimentally. The simulations indicate that the amplitudes and time-courses are primarily determined by the chemical reaction rates that characterize acetylcholine interactions with receptor and esterase and that these interactions occur under nonequilibrium conditions. Approximately 50% of the total ion channels in the initial reaction space are predicted to be opened at the peak endplate current. The cooperative opening of ion channels by acetylcholine requires that acetylcholine be introduced into the cleft in discrete, concentrated elements. Virtually all the open channels are confined to the initial reaction space, although acetylcholine-bound receptor sites can be much more widely distributed.
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PMID:Quantitative simulation of endplate currents at neuromuscular junctions based on the reaction of acetylcholine with acetylcholine receptor and acetylcholinesterase. 26 18

We have studied the properties of N-7-(4-nitrobenzo-2-oxa-1,3-diazole)-omega-aminohexanoic acid beta-(N-trimethylammonium)ethyl ester, a fluorescent analog of acetylcholine at the cellular level by using pharmacological and electrophysiological techniques and at the molecular level by measuring the kinetics of interaction with solubilized acetylcholine receptor and with acetylcholine esterase (EC 3.1.1.7). The fluorescent drug is a powerful agonist of acetylcholine at the neuromuscular junction and also strongly desensitizes muscle fibers. Interaction with acetylcholine receptor is accompanied by large changes in the drug's fluorescence. From the kinetics of interaction studied by means of a stopped-flow fluorimeter with laser light source, we obtained a second-order forward rate constant in excess of 1 X 10(8) M-1 sec-1 and an initial dissociation rate constant (k1) of 0.5 sec-1 for receptor from Electrophorous electricus. Interaction of this analog with acetylcholine esterase from E. electricus is accompanied by a transient decrease in fluorescence followed by an increase leading to a stable plateau value at a level near the original one. The initial decrease in fluorescence followed second-order kinetics with k2 of the order of 10(9) M-1 sec-1. The slower consecutive reaction which could be blocked by phosphorylation of the esteratic site, was of first order with k1 = 0.05 sec-1.
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PMID:NBD-5-acylcholine: fluorescent analog of acetylcholine and agonist at the neuromuscular junction. 31 97

1. Disc electrophoresis was used to determine the esterase isoenzymes present in adults of the strigeoid trematode Alaria marcianae (La Rue, 1917). 2. Eight esterase bands were found with alpha-naphthyl acetate as the substrate and Fast Blue RR as the dye. 3. From results obtained with inhibitors, four different types of esterases were tentatively identified; cholinesterase (one band), ali-esterase or B-type (one band), arylesterase or A-type (2 bands) and acetylesterase or C-type (4 bands).
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PMID:Electrophoretic separation of esterases of Alaria marcianae (La Rue, 1917) (Trematoda). 31 43

The pituitary glands of two urodelan species (Mertensiella caucasica, Triturus cristatus) and one one caecilian species (Chthonerpeton indistinctum) were examined with histological (Alcian blue, Brookes' trichrome stain), enzyme histochemical (acid phosphatase, alpha-naphthylacetate-esterase, acetylcholinesterase) and immunofluorescence techniques (anti-carp GTH, anti-ovine prolactin, anti-synthetic alpha-MSH). In the pituitary gland of Mertensiella and Triturus six chromophilic cell types could be distinguished. A strong fluorescence was observed in the MSH-, GTH- and TSH-cells. In the pituitary gland of Chthonerpeton only five chromophilic cell types could be distinguished: in the rostral part of the pituitary gland the B3-cell; in the basal region of the central area the B2-cell; dorsocaudally the B1-cell. The acidophilic cells were found in the central and caudal part of the pars distalis. The basophils of the pars intermedia could be observed in the dorsocaudal part of the pituitary gland surrounding the neurohypophysis. All acidophilic cells showed a strong immunofluorescence with anti-ovine prolactin (LTH).
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PMID:Histological, immuno- and enzyme-histochemical investigations on the adenohypophysis of the urodeles, Mertensiella caucasica and Triturus cristatus and the caecilian, Chthonerpeton indistinctum. 34 44

Mouse sternomastoid muscles were incubated with diisopropylfluorophosphate (DFP) in vivo, and the time course of recovery was studied using histochemistry, EM autoradiography and physiology. We found that: (1) the ability of the muscle to sustain tetanus in response to nerve stimulation is eliminated when the esterases at the neuromuscular junctions are saturated with DFP. This ability is regained partially when less than 10% of the DFP-binding sites have recovered. (2) There is a positive correlation between the frequency of stimulation at which the tetanic response can be maintained and the extent of acetylcholinesterase (AChE) recovery. (3) Tetanic responses at fusion frequency (about 100 Hz) appear indistinguishable from controls with only about 25% of normal AChE. (4) Butyrylcholinesterase (BuChE) possibly of Schwann cell origin recovers more rapidly than does AChE. (5) The muscle shows fine structural changes involving Z band dissolution and the breakdown of sarcoplasmic reticulum within hours after esterase inactivation. (6) This myopathy reaches a peak at three days after esterase inactivation and is almost fully recovered by two weeks. (7) It can be eliminated if, at the time of esterase inactivation, the nerve is cut or the acetylcholine receptors at the endplate are inactivated by alpha-bungarotoxin. We suggest that the myopathy, seen after DFP, is mediated by Ca2+ fluxes due to prolonged action of acetylcholine (ACh) in the absence of esterases.
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PMID:Endplates after esterase inactivation in vivo: correlation between esterase concentration, functional response and fine structure. 43 72

A study was undertaken to determine whether the antiesterase activity of echothiophate iodide would prevent the conversion of dipivefrin to epinephrine. Dipivefrin was administered singly and in combination with echothiophate to 24 adult rabbits. Administration of dipivefrin lowered the intraocular pressure (IOP) 8 +/- 1 mm Hg (P less than .001). When echothiophate was given before and concomitant with dipivefrin, there was no further decrease in IOP compared with that produced by echothiophate alone (5 +/- 1 mm Hg). Addition of epinephrine to eyes receiving dipivefrin plus echothiophate resulted in a significant additional decrease in IOP of 4 +/- 1 mm Hg (P less than .001). When echothiophate was given after dipivefrin had lowered the IOP and both drugs were continued, the IOP rose to baseline levels. These results fit the theory that the esterase converting dipivefrin to epinephrine is inactivated by cholinesterase inhibitors. The clinical use of cholinesterase inhibitors and dipivefrin may be contraindicated.
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PMID:Dipivefrin and echothiophate: contraindications to combined use. 48 20

The application of the histochemical thiolacetic acid method on plasmodia of the acellular slime mold Physarum confertum leads to the formation of lead sulfide deposits at the outer cytoplasmic surface and its invaginations. The reaction cannot be reduced by esterase- and cholin/acetylcholinesterase inhibitors. Successive application of lead and sulfide in the absence of substrate results in a lead sulfide deposit at the same sites indicating that the underlying reaction is based on an artificial adsorption of ions at the surface of the plasmodium. This finding means that the thiolacetic acid method is not suited for the demonstration of a surface-associated esterase/cholinesterase activity in slime molds. Based on the ion adsorption property of the surface of plasmodia a simple method is developed for the "in toto" demonstration of the plasmamembrane-invagination-system in aceullar slime molds.
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PMID:[On the problem of histochemical demonstration of esterase activity by the thiolacetic acid method in the acellular slime mold Physarum confertum (author's translation)]. 55 62

The enzyme behaviour of acetylcholinesterase in diaphragm and that of unspecific esterase in liver, testes and hypothalamus were investigated in view of various organophosphates on total-preparation and cryostat section of 10 male wistar rats. It had pointed out that the blockade was dependent upon the concentration as well as the acid possessing P = O-binding proved to be appropriate for in vitro experiment. The most intense blockade of unspecific esterase was reached in tanycytependym of the third ventricle. The acetylcholinesterase in the motor endplate of diaphragm was less influenced. From these findings follows that a direct conclusion for in vivo toxicity can not be drawn from in vitro results. The significance of the chemical structure of the substance utilized was discussed concerning its inhibitory effect.
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PMID:[Histochemical behavior of acetylcholinesterase in the diaphragm and that of unspecific esterase in the hypothalamus, testes and liver of rats in relation to organophosphates]. 56 92


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