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

An aqueous two phase polymer system (Dextran-polyethyleneglycol system was developed for isolation of plasma membrane fraction from nerves of the crayfish, Procamburus clarkii. The polymer system effectively reduced both mitochondrial and endoplasmic reticulum marker enzyme activity from a crude membrane fraction. The similar enrichment of (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) was shown by the polymer system as well as by the sucrose density gradient centrifugation. The purified plasma membrane fraction (PM) was obtained using the polymer system followed by sucrose density gradient centrifugation. The PM fraction had a high specific activity of (Na + K+)-ATPase of up to 17 times that in the homogenate, with smaller contamination by mitochondria and endoplasmic reticulum enzyme activities than any other membrane fraction. Electron micrographs of the PM fraction also supported the above evidences. The protein recovered from the PM fraction amounted to 1.1% of the total protein in the homogenate. The specific activity of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) in the membrane fractions was less increased than that of (Na+ + K+)-ATPase. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis suggested that polypeptide chains of estimated molecular weight 115,000 and 31,000 were enriched in the plasma membranes of the crayfish nerves.
 ...
PMID:Isolation of neuronal plasma membranes from the crayfish Procamburus clarkii, with an aqueous two phase polymer system followed by sucrose density gradient centrifugation. 22 29

Conley et al., in 1971, described a special type of melanoma characterized by a superficial melanic lesion at the onset; repeated local relapses as subcutaneous tumorations with an histological picture closely resembling an atypical fibroxantoma or fibrosarcoma. After a review of all the published material the autors presents a personal case with the clinical, histological and evolutive characteristics of this disease. The most interesting findings of the published case are the following: The special stains for the melanocytes (silver stain, Dopa, tyrosinase and cholinesterase) were all negative. There was an intense positivity for the lisosomal enzymes (non specific sterases, and acid phosphatases). The ultrastructural study of the tumoral tissues as well as the cells of cultures showed abundant cells with tumoral aspects, with prominent nucleoli somewhat dilated granular endoplasmic reticulum, myelin-like figures, lipidic vacuoles and abundant lisosomes. No melanosomes or premelanosomes were observed. Beside these tumoral cells abundant typical fibroblastic elements were found. There was a great amount of collagen fibers with periodicity superior to the normal. The conclusion is that the desmoplastic melanoma must be considered as a tumor of mesenchimatous origin intervening in its development multiple local and general factors.
 ...
PMID:[Desmoplastic melanoma]. 34 19

In this ontogenetic study the neurons of layer VIb of rodent somatosensory cortex have been characterized using acetylcholinesterase (AchE) histochemistry, Golgi, and electron microscopic techniques. Already, at birth, the neurons were found to be AchE-rich. They contain presumed AchE reaction product within their granular endoplasmic reticulum. These cells send fine axons upwards towards the subpial layer where they terminate in a dense, AchE-rich, fiber plexus. In chronically undercut cortex, AchE staining persists in layer VIb neurons and in the subpial fiber plexus. These observations continue to support the view that there is an intrinsic neuronal circuit connecting layer VI with I in immature neocortex. The findings also raise the possibility that the putative circuit is cholinergic.
 ...
PMID:Acetylcholinesterase-containing neurons of layer VIb in immature neocortex: possible component of an early formed intrinsic cortical circuit. 51 68

The ultrastructural localization of acetylcholinesterase (AChE) was studied in the cerebellar cortex of the quail by means of histochemical method. The greater amount of AChE was detected at leve of the molecular layer in the intracellular spaces between parallel fibers and between parallel fibers and dendritic terminals. Many neurons showed intracellular localization of enzyme activity: the AChE positive neurons were all Golgi cells, most stellate the basket cells and different aliquots of Purkinje and granule cells. The enzymatic activity was usually localized in the cisternae of endoplasmic reticulum, in the nuclear envelope (but this last localization was not present in Purkinje cells- and sometimes in the Golgi apparatus; reaction granules were usually scarce in the different dendritic branches ramifying in the molecular layer. On the basis of the ultrastructural pattern of AChE distribution, some considerations are developed on the methodological aspects concerning the reliability of histochemical methods, the differences recorded at light and electron microscope level, the problems related to extracellular localization of enzyme, the difficulty of establishing a precise correlation between AChE localization in a cerebellar neuron and its possible cholinergic and/or cholinoceptive nature.
 ...
PMID:Ultrastructural pattern of acetylcholinesterase distribution in the cerebellar cortex of the quail. 60 95

The ultrastructural localization of acetylcholinesterase (AChE) has been studied in the superior cervical ganglion of the rat. Previous descriptions of the general pattern of localization were confirmed, but in addition, AChE reaction product was found within vesicles in preganglionic nerve terminals, and in pinocytotic vesicles and along the basement lamina of capillaries. There was indication of a continuity between AChE reaction product in the cisternae of the rough endoplasmic reticulum of the principal ganglion cells and extracellular reaction product. These observations are discussed with particular reference to AChE as a secretory protein.
 ...
PMID:Intracellular localization of acetylcholinesterase in nerve terminals and capillaries of the rat superior cervical ganglion. 65 Feb 61

By employing biochemical assay and histochemical enzyme techniques the effect of preganglionic sympathectomy on the cholinesterase (ChE) activity in the superior cervical ganglia of rats and hamsters was investigated. Biochemical assays indicate that the ChE activity in the superior cervical ganglia of adult rats and hamsters is 57.19 and 28.63 respectively (expressed in micron moles acetylcholine hydrolyzed per min per g of tissue); two weeks after preganglionic denervation, about 50% and 60% of ChE activity are lost respectively. Histochemical enzyme examination reveals that in the rat superior cervical ganglion, the majority of the neurons are adrenergic with weak to moderate acetylcholinesterase (ACHhE) reaction and the minority of the neurons are cholinergic with strong AChE activity, while only one type of adrenergic neurons exhibits a weak AChE activity in the hamster superior cervical ganglion. The AChE activity is localized in the perinuclear area, in the cisternae of the rough surfaced endoplasmic reticulum, in the Golgi complex and on the plasma membrane of the hamster's neurons; it is mainly locolized in the cisternae of the rough surfaced endoplasmic reticulum of the rat's neurons. AChE reaction product is also detected on the aeolemmal membranes of the preganglionic nerve fibers in the sympathetic ganglia of rats and hamsters. After preganglionic sympathectomy, the AChE activity in the adrenergic neurons and in the preganglionic unmyelinated nerve fibers is markedly reduced, whereas the cholinergic neurons and preganglionic myelinated nerve fibers remain unchanged. On the basis of these results two conclusions have been reached: (1) The fact that strong AChE activity localized in the cholinergic neurons and preganglionic myelinated fibers is not influenced by denervation, suggests that these structures are able to produce AChE. (2) The reduction of AChE activity in the rat and hamster superior cervical ganglia two weeks after preganglionic denervation, observed by histochemical examination, can be correlated with a concomitant measurable reduction determined by biochemical assays.
 ...
PMID:Effect of preganglionic sympathectomy on the cholinesterase activity in the superior cervical ganglia of rats and hamsters. 87 Feb 6

The electronhistochemical localization of the cholinesterases of developing chick heart muscle cells has been studied with the aid of a substrate which incorporates an enzyme-susceptible thiolester group and a diazonium group into the same molecule. The embryonic chick heart exhibits cholinesterase activity from Hamilton-Hambruger stage 3 through to four days post hatching. Although enzyme activity is not demonstrated in every location at all stages studied, it has been observed on the nuclear envelope, golgi complex, rough and smooth endoplasmic reticulum, mitochondria and myofilaments. A change in the type of activity has been demonstrated, acetylcholinesterase is found during the first fourteen days of development but thereafter, non-specific cholinesterase is seen instead. As nerves have not been found in relation to the working myocardium, further support is given to the concept that an acetylcholine-cholinesterase system of myogenic origin is involved in spontaneous contraction. Consideration of the distribution of enzyme within the myocardial cell, raises the possibility that cholinesterase may be concerned in a regulatory mechanism of protein synthesis, a suggestion made previously in connection with liver cells.
 ...
PMID:The cytochemical localization of cholinesterase activity in the developing chick heart. 95 76

Explants of 10--12 day chick embryo spinal cord were cultured by coverslip-roller tube method for 3-80 days. The cellular and subcellular localization of acetylcholinesterase activity in cultured neurons was studied by the thiocholine techniques of Karnovsky and Roots and Lewis and Shute. At the light microscopic level, acetylcholinesterase was demonstrated in the neurons of both ventral and dorsal horn regions. Occasionally neurons migrated in the outgrowth zone exhibited strong intracellular activity. At the electron microscopic level, acetylcholinesterase activity was found in the nuclear envelope, granular endoplasmic reticulum and the Golgi apparatus of the neurons. No enzyme reaction was detected in the glial cell cytoplasm.
 ...
PMID:Acetylcholinesterase distribution in chick spinal cord cultures. A light and electron microscope study. 95 84

Release of peroxidase from secretory cells of rat lacrimal gland upon cholinergic stimulation was studied in vitro with single lobules and isolated cells (lacrimocytes). Isolated lobules, kept in Eagle's medium, remain structurally intact and reaction product of peroxidase is confined to cisternae of rough endoplasmic reticulum, elements of the Golgi apparatus, and all secretory granules. Morphologically, exocytosis occurs by membrane fusion and discharge of granule content. The highest rate of peroxidase released from lobules is observed at 10(-4) M carbamylcholine. The specific activity of peroxidase released into the medium is fourfold higher as compared to the lobules. Release of peroxidase is suppressed by atropine when added before or after the addition of carbamylcholine. At 4 degrees C, no peroxidase release occurs upon cholinergic stimulation. The exocytotic release of peroxidase is dependent on energy supply, as indicated by substantial inhibition (at 37 degrees C) under anoxic conditions or in the presence of dinitrophenol, KCN, or carboxyatractyloside. Furthermore, the process is sensitive to colchicine and vinblastine. Isolated lacrimocytes, consiting of 95% secretory acinar cells, are prepared by digestion with collagenase, hyaluronidase, and trypsin. They retain the characteristic polarity of secretory cells in situ, and localization of peroxidase is the same as in lobules. Since isolated lacrimocytes respond to cholinergic stimulation in the same way as lobules, the receptors are not damaged by the isolation procedure and appear to be associated directly with the exocrine cell. Oxygen uptake by isolated lacrimocytes is about 14 nmol O2 X min-1 X 10(-6) cells; it is about doubled by uncoupling with dinitrophenol. Oxygen uptake rises by 20-30% above the resting rate upon cholinergic stimulation. This additional uptake is suppressed by atropine or by added cholinesterase, indicating that continuous receptor occupancy may be required for the energy demand by exocytosis. On the basis of the specific activity of peroxidase in the medium, the energy demand resulting from cholinergic stimulation is estimated to be 0.08 mumol ATP (or energy-rich phosphate bonds) per microgram of protein released from the lacrimocytes.
 ...
PMID:Exocytosis in secretory cells of rat lacrimal gland. Peroxidase release from lobules and isolated cells upon cholinergic stimulation. 95 71

Retinae of guinea pigs from the fortieth day of gestation to one day postnatally were processed for the localization of cholinesterases in the electron microscope according to the method of Lewis and Shute ('66). Selective inhibition served to distinguish acetylcholinesterase from non-specific cholinesterase activity. Acetylcholinesterase activity was found initially in small amounts in some regions of the outer plexiform layer at the fortieth day of gestation. At later stages it increased in distribution being observed at some photoreceptor terminals and in non-synaptic regions of the layer. Activity was less intense initially in the inner plexiform layer but increased rapidly so that by birth it encompassed a majority of processes. Perikarya of horizontal and some amacrine and ganglion cells possessed acetylcholinesterase activity in their nuclear envelope and rough endoplasmic reticulum. The possible role of the enzyme in inhibitory circuits of the fetal retina is discussed.
 ...
PMID:The localization of cholinesterase in the retina of the fetal and newborn guinea pig. 97 11


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