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)

A novel method of determining N-terminal amino acids in proteins is introduced. Reductive methylation of a protein with radiolabeled formaldehyde methylates both the alpha-amino group of the N-terminal amino acid and the epsilon-amino groups of Lys residues. The radiomethylated amino acids are stable to acid hydrolysis, and each of 16 possible hydrolysis-stable N-terminal amino acids can be identified by the unique elution positions of its N alpha-methyl and N alpha,N alpha-dimethyl derivatives with an appropriate amino acid analyzer elution schedule. The technique is at least as sensitive as other N-terminal amino acid determinations and, in addition, permits a quantitative evaluation of the number of N-terminal groups in a sample. Reductive methylation of bovine serum albumin revealed N-terminal Asp at a stoichiometry of 0.97 amino acid residue per polypeptide, while methylation of prolactin resulted in 0.86 residue of N-terminal Thr per polypeptide. Human erythrocyte acetylcholinesterase contained two N-terminal amino acids with stoichiometries of 0.66 Glu and 0.34 Arg per 70-kDa subunit. Identification of Glu as the principal N-terminus of acetylcholinesterase was confirmed by Edman sequencing.
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PMID:Quantitative identification of N-terminal amino acids in proteins by radiolabeled reductive methylation and amino acid analysis: application to human erythrocyte acetylcholinesterase. 403 98

Di-isopropylfluorophosphate (DFP) labeled with phosphorus-32 was applied to fragments of the diaphragm and sternomastoid muscles of the mouse, in conditions in which it saturated all available sites at the motor endplates. After adequate washing and exchange with unlabeled DFP, single endplates were obtained by microdissection and their radioactivity was found by beta track radioautography. The number of sites phosphorylated by DFP-(32)P per endplate was relatively constant for each muscle: in the sternomastoid, about 9 x 10(7) sites per endplate, in the diaphragm, about 3 x 10(7). Reaction with DFP-(32)P was abolished by prior treatment with unlabeled DFP. Labeling was unaffected by prior fixation in formaldehyde, but was inversely proportional to the time of incubation in the Koelle staining medium, when this preceded labeling. The contribution of acetylcholinesterase (AChase) to this total number of DFP-reactive sites was determined by three methods. The first involved reactivation of the phosphorylated AChase by pyridine-2-aldoxime methiodide (2-PAM), in conditions in which the reactivation of other enzymes would be insignificant. The other two methods involved protection of the active centers of AChase from phosphorylation by labeled DFP by use of 284C51, an inhibitor highly specific for this enzyme, or by use of eserine. Each of these methods indicated that about 35% of the DFP-reactive sites at endplates of the sternomastoid and diaphragm are AChase. The mean number of AChase molecules was thus found to be 3.1 x 10(7) and 1.1 x 10(7)per endplate in sternomastoid and diaphragm, respectively. No significant reaction of labeled DFP with muscle and nerve was observed. Mast cells in the muscle had a concentration of DFP-reactive sites far higher than the endplates.
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PMID:Quantitative studies on enzymes in structures in striated muscles by labeled inhibitor methods. I. The number of acetylcholinesterase molecules and of other DFP-reactive sites at motor endplates, measured by radioautography. 418 15

Neuroepithelial bodies (NEB) in 29-day fetal rabbit lung were examined by light microscopy and cytochemistry to demonstrate their structural and biochemical properties in situ. Longitudinal sections of NEB at airway bifurcations demonstrated their chemoreceptor-like appearance. Furthermore, the cytochemical presence of serotonin, acetylcholinesterase, formaldehyde-induced fluorescence, and silver-staining properties demonstrated the neural-like biochemical properties of NEB cells. Forty-one NEB and eight single neuroendocrine cells from whole fetal lungs were examined ultrastructurally. Juxtaluminal junctional complexes composed of tight and intermediate junctions, desmosomes, and cytoplasmic filaments were demonstrated in the corpuscular-shaped NEB. Basal bodies were apparent in NEB cell cytoplasm; cilia extended from NEB cells. Dense-core vesicles (DCV) were of at least three types: type 1, type 2, and enterochromaffin type. The majority of epithelial cells adjacent to NEB in near-term airway epithelium were undifferentiated, with large amounts of glycogen. However, ciliated cells were adjacent to some small NEB and single neuroendocrine cells; mucus or Clara-type cells were not observed. NEB isolated by collagenase treatment revealed an intact organoid structure, DCV, and desmosomes and retained their argyrophilia and formaldehyde-induced fluorescence. NEB were recovered in cell fractions separated by unit gravity that had cells in clumps of four or more. One to five NEB stained with silver in cytocentrifuge preparations of control, mixed cells, whereas up to 20 intact NEB were demonstrated in the clump-containing, separated fractions. We propose that isolated NEB retain certain biochemical and metabolic properties similar to those of their counterparts in situ. Serotonin and 5-hydroxyindole acetic acid were found by high-performance liquid chromatography analysis in the fractions containing NEB, and amine precursor uptake and decarboxylation (APUD) activity were demonstrated. Moreover, muscarinic cholinergic receptors were detected, consistent with the occurrence of acetylcholinesterase in NEB. The elution profile of bombesin radioimmunoactivity substantiated that isolated fetal rabbit NEB contained this neuropeptide and that NEB were enriched by unit gravity sedimentation. These studies suggest that NEB are structurally and functionally developed before other cell types in immature airway epithelium and can be isolated as intact organoids, which retain some of their structural and metabolic integrity.
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PMID:Morphological and cytochemical characterization of neuroepithelial bodies in fetal rabbit lung. I. Studies of isolated neuroepithelial bodies. 613 13

A modified method of Ellman's reaction with a continuous flow was used to study the cerebral cholinesterase activity in its biological environment with rat brain slices including the striatum. Comparative studies were performed under various conditions of flow and substrate concentrations (acetylthiocholine bromide) and with or without formaldehyde fixation. We could thus measure either the inhibition rate of cerebral ChE by paraoxon or MPT or the reactivation rate by some oximes in the presence of substrate and after removing excess inhibitor.
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PMID:In vitro study of organophosphorus inactivators of membrane acetylcholinesterase and of reactivating pyridinium-oximes using rat brain slices. 641 4

The pedal ganglion is a peripheral ganglion which gives rise to the innervation for both the somatic and visceral organs of the Mytilus foot. In the present study, different histofluorescence methods for the demonstration of monamines (formaldehyde-glutaraldehyde followed by polyethylene glycol embedding; aluminium-formaldehyde; Falck) and acetylcholinesterase histochemistry were applied in order to characterize the neuronal population of the ganglion. The fluorescence methods employed showed that the cortical region of the pedal ganglion is composed of roundish cells; these mainly contained an orange autofluorescent pigment. Yellow-fluorescing cells were scattered in the anterior region of the cortex, but they were more numerous and arranged in clusters in the posterior region. Green-fluorescing cells were mainly located at the border between the cortex and neuropile and in the neuropile itself, where a rich plexus of beaded green-fluorescing fibres was also present. Of the three methods, that using formaldehyde-glutaraldehyde followed by embedding in polyethylene glycol gave the best preservation of morphological details. Acetylcholinesterase histochemistry showed the presence of positive cells and fibres mainly in the anterior region of the ganglion.
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PMID:Histochemical localization of monoamines and cholinesterases in Mytilus pedal ganglion. 652 95

The aluminium-formaldehyde (ALFA) histofluorescence method reveals an extensive plexus of brilliant greenish monoaminergic elements in the glandular zones of the Mytilus foot, while only scanty nerve fibres are acetylcholinesterase-positive. By electron microscopy, bundles of nerve fibres can be seen i) in close connection with the intrinsic musculature located in the connective septa among the glands, and ii) near the cell bodies and necks of all the byssus glands. The nerve fibres show varicosities containing three types of vesicles: small clear (50-60 nm), small granular (80-90 nm), and large granular (160-200 nm). The regions of close apposition between nerve terminals and muscle or gland cells generally do not show typical pre- or postsynaptic specializations. Along the pedal groove, mainly in the proximal two thirds of the foot, peripheral bipolar neurons can be detected, both by fluorescence and electron microscopy.
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PMID:Histochemical and ultrastructural study on the innervation of the byssus glands of Mytilus galloprovincialis. 661 74

The presence of nerve fibers was investigated in porcine and human atrio-ventricular valves by AChE technique, formaldehyde-induced fluorescence, en bloc silver and gold chloride impregnation and electron microscopy. Elaborate nerve plexuses were observed in every leaflet and in some chordae tendineae of all the samples examined, without significant species differences in the pattern of innervation. The presence of a sensory innervation was inferred from the demonstration, in whole mount samples processed for acetylcholinesterase, of thick myelinated nerve fibers and of endings with dot-like or brush-like appearance. Moreover the results of the combined histochemical and ultrastructural methods showed the existence of both cholinergic and adrenergic efferent nerve fibers. Nerve varicosities with clear or dense-cored vesicles were frequently observed in proximity to blood vessels and to cardiac and smooth muscle bundles, which therefore can be considered as the targets of the efferent nerve supply. The complex pattern of the innervation herein demonstrated suggests the existence of a nervous control of valvular function through the regulation of contractile elements.
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PMID:Histochemical and ultrastructural study on the innervation of human and porcine atrio-ventricular valves. 674 55

Most principal neurons in sympathetic ganglia are noradrenergic. A small population, especially those that innervate sweat glands in rat footpads, are cholinergic. We have characterized the innervation of the glands in adult and developing rats to determine whether sympathetic neurons undergo a transition from noradrenergic to cholinergic during normal development as has been observed in culture. In adult rats, the fibers innervating sweat glands exhibited strong acetylcholinesterase (AChE) staining and vasoactive intestinal peptide (VIP)-like immunoreactivity. None of the axons contained endogenous catecholamines detectable with formaldehyde-induced fluorescence or permanganate fixation. However, like cholinergic sympathetic neurons in culture, all axons could take up and store exogenous catecholamine. The sweat glands and their innervation develop postnatally. At 7 days, the axons innervating sweat glands possessed endogenous catecholamine histofluorescence and small granular vesicles but not AChE or VIP. By 14 days, AChE and VIP staining was pronounced. In contrast, catecholamine fluorescence and the number of small granular vesicles were reduced, and by 21 days they were absent. Further, neonatal treatment with 6-hydroxydopamine, a toxic norepinephrine congener, resulted in the loss of cholinergic as well as noradrenergic sympathetic innervation. These observations are consistent with a transition from noradrenergic to cholinergic function in vivo.
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PMID:Development of cholinergic sympathetic neurons: evidence for transmitter plasticity in vivo. 683 80

This study investigated the cholinesterasic reactivity of catecholamine neurons in the rat hindbrain with the aid of a two-step histochemical procedure. First, catecholamine cells were visualized by their formaldehyde/glutaraldehyde induced specific histofluorescence and then poststained in the same tissue with a thiocholine technique for acetylcholinesterase (AChE). Processing the vibratome-sectioned tissue in phosphate buffer subsequent to initial aldehyde fixation permitted satisfactory preservation of both amine fluorophores and esterasic reactivity. Our results, in both randomly sampled and serially sectioned material, unequivocally establish the presence of AChE in all pontomedullary cell groups emitting catecholamine fluorescence, the majority of which are known to consist of noradrenaline perikarya. Hence in contrast to previous reports the occurrence of AChE in central noradrenaline neurons appears to be generalized. The intensity of histofluorescence and esterasic staining were uncorrelated in most regions. It remains for future study to determine whether AChE in brain catecholamine neurons indicates their cholinoceptivity or subserves the catabolism of other neuromediators such as substance P.
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PMID:Acetylcholinesterase in pontomedullary catecholamine neurons of the adult albino rat. 706 9

The intraglandular distribution of adrenergic and cholinergic nerve fibers was studied histochemically in the parotid, mandibular, and sublingual glands of six species of edentates belonging to the three families that comprise the order; namely the Dasypodidae (armadillos), the Myrmecophagidae (anteaters), and the Bradipodidae (sloths). The following histochemical techniques were used: (a) acetylcholinesterase reaction for the demonstration of cholinergic fibers; (b) formaldehyde- and glyoxylic acid-induced fluorescence for the demonstration of adrenergic fibers. In addition, norepinephrine (NE) was assayed fluorimetrically in the mandibular and parotid glands of the armadillo. A network of acetylcholinesterase-positive nerve fibers surrounds the intra- and interlobular ducts and endpieces of all glands; it is of low density in the mandibular and sublingual gland of the sloth, of high density in the sublingual gland of the anteater and of moderate density in the remaining glands. A vascular cholinergic innervation occurs in all salivary glands. Although present around the vessels, adrenergic new fibers were virtually absent from the parenchyma of all glands, even after in vitro incubation of glandular tissue with NE or after administration of NE to armadillos previously treated with a monoamine oxidase (MAO) inhibitor. Consistent with this fact, the amount of NE present in the parotid and mandibular gland of the armadillo was extremely low. These findings may indicate that the salivary secretion in the edentates is regulated by the parasympathetic rather than by the sympathetic nervous system.
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PMID:Autonomic innervation of salivary glands in the armadillo, anteater, and sloth (Edentata). 724 6


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