Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were assayed in samples dissected from sagittal sections through rat superior colliculus. The magnitude of ChAT activity was about half to equal that found in rat whole brain in all layers except stratum griseum intermediale, where the average activity was higher than whole brain. AChE activity was three to four times that found in rat whole brain in superficial layers and about the same as average brain in deeper layers, except in the statum griseum intermediale, where the average activity was about twice whole brain. Rostral-caudal gradients in both ChAT and AChE activities occurred in stratum griseum intermediale, with activities in the caudal region of some animals as high as four times those in the rostral. ChAT activity in samples associated with locations of patches or spots of AChE staining product in stratum griseum intermediale was significantly higher than in samples from "nonpatch" regions. Results are discussed relative to inputs into the colliculus, whose terminations may correlate in location with the distributions of the enzyme activities.
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PMID:Distributions of choline acetyltransferase and acetylcholinesterase activities in layers of rat superior colliculus. 400 17

Choline acetyltransferase activity and localization of acetylcholinesterase and [3H]quinuclidinyl benzilate binding sites (muscarinic receptors) in rat facial nuclei were examined 2 weeks after right facial nerve transection or sham control surgery. Choline acetyltransferase activity in the right facial nucleus of nerve-transected rats was only one-third of that in the left nucleus. Histochemical observations revealed loss of acetylcholinesterase from most motoneurons and neuropil of the right facial nucleus after axotomy. Autoradiographic grains, marking muscarinic receptors, were likewise depleted substantially from this region. Facial nuclei of control animals were identical with respect to all of these neurochemical measures and undistinguishable from the left facial nucleus of nerve-transected rats. Cholinergic enzymes are known to be synthesized by motoneurons, but the source of muscarinic receptors in the facial nucleus is not known. Since all three proteins are depleted from the facial nucleus after axotomy of motoneurons, it is concluded that these cells produce cholinergic enzymes and muscarinic receptors. Synthesis of muscarinic receptors by facial motoneurons could indicate these neurons are cholinoceptive. Axotomy should be a useful tool for determining which other neurotransmitter receptors are produced by facial motoneurons and efferent neurons in other cranial nerve nuclei.
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PMID:Effect of facial nerve transection on acetylcholinesterase, choline acetyltransferase and [3H]quinuclidinyl benzilate binding in rat facial nuclei. 402 35

The enzyme choline-O-acetyltransferase catalyses the biosynthesis of acetylcholine from acetyl coenzyme A and choline and is considered as one of the best markers for cholinergic nerve endings. The distribution of this enzymatic activity was analysed during the purification of plasma membranes of purely cholinergic nerve endings isolated from the electric organ of the fish Torpedo marmorata. This tissue, which receives a profuse and purely cholinergic innervation, can be considered as being a "giant" neuromuscular synapse. The isolated nerve endings (synaptosomes) were first osmotically disrupted and their plasma membranes isolated by equilibrium density centrifugation (discontinuous followed by continuous sucrose gradients). Choline acetyltransferase activity was found to exist in three forms: (1) a soluble form (the major one) present in the cytoplasm of the nerve endings, (2) a form which is ionically associated with membranes and which can be solubilized by washing exhaustively the membrane fraction with solutions of high ionic strength (0.5 M NaCl) and (iii) a form which is non-ionically bound to membranes and cannot be solubilized with high salt solution. The soluble and the non-ionically bound activities exhibited very similar affinities for choline (1.34 and 1.64 mM, respectively). The non-ionically membrane-associated form of choline acetyltransferase was found to "copurify" with the cholinergic synaptosomal plasma membranes of Torpedo, its specific activity being increased from 122 (crude fraction) to 475 (purified membrane fraction) nmol/h/mg protein. An enrichment was also observed for another cholinergic marker, the enzyme acetylcholinesterase, but not for the nicotinic receptor to acetylcholine, a marker for postsynaptic membranes. No choline acetyltransferase activity could be detected in preparations of synaptic vesicles that were highly purified from the electric organ. Also, the non-ionically associated form of choline acetyltransferase activity was hardly detectable (2.4 nmol/h/mg protein) in fractions enriched in axonal membranes prepared from the cholinergic electric nerves innervating the electric organ. The partition into soluble and membrane-bound activity was also analysed for choline acetyltransferase present in human placenta, a rich source for the enzyme but a non-innervated tissue. In this case the great majority of the enzyme appeared as soluble activity. Very low levels of non-ionically membrane-bound activity were found to be present in a crude membrane fraction from human placenta (2.8 nmol/h/mg protein).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Membrane-bound choline acetyltransferase in Torpedo electric organ: a marker for synaptosomal plasma membranes? 402 40

Cholinergic enzymes and muscarinic receptors in nuclei of rat medulla oblongata were examined after unilateral vagotomy to determine their association with efferent vagal neurons. Vagotomy caused an ipsilateral depletion of acetylcholinesterase from the dorsal motor nucleus of the vagus (DNV) and the nucleus ambiguus (NA). Choline acetyltransferase activity was reduced in ipsilateral DNV, nucleus tractus solitarius and rostral NA. Muscarinic receptor localization by autoradiography with [3H]quinuclidinyl benzilate (QNB) revealed marked intranuclear variations in receptor density. Vagotomy had no effect on the QNB binding pattern. Loss of cholinergic enzymes is a consistent response of motor and preganglionic autonomic neurons to axotomy. Depletion of muscarinic receptors is an additional component of axon reaction in brain stem motoneurons. Accordingly, previous studies have shown a decrease in neurotransmitter-related proteins after axotomy of motoneurons. In the present study, cholinergic enzymes were depleted from axotomized vagal neurons but receptors were not. It is concluded that muscarinic receptors in the DNV and NA are not associated with vagal efferent neurons.
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PMID:Effect of vagotomy on cholinergic parameters in nuclei of rat medulla oblongata. 402 5

Choline acetyltransferase and acetylcholinesterase activities in the septo-temporal regions of the rat hippocampus, and in the forebrain of mice were significantly decreased in senescent as compared with adult animals. A four week treatment of aged rats or mice with Hydergine resulted in the restoration of choline acetyltransferase activity.
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PMID:Deficits in cholinergic enzyme activities in septo-temporal regions of the senescent rat hippocampus, and in the forebrain of aged mice: effect of chronic Hydergine treatment. 409 44

1. Acetylcholine (ACh), cholinesterases and choline acetyltransferase (choline acetylase) were estimated in the neural lobe and hypothalamus of the adult male rabbit. Acetylcholine was also estimated in the neural lobes and hypothalami of some other mammals.2. Acetylcholine-like activity was measured by bio-assay using the leech dorsal muscle preparation.3. Characterization experiments indicated that about 90% of the activity measured was due to acetylcholine.4. Mean acetylcholine content in the neural lobe of the rabbit, after extraction with perchloric acid, was 4.38 +/- 0.98 mug/g fresh tissue, and 4.87 +/- 1.53 mug/g in the hypothalamus.5. Acetylcholine was also found to be present, in comparable concentrations, in the neural lobe of man and in the neural lobes and hypothalami of ox, rat and hedgehog.6. Acetylcholinesterase, present in the neural lobe and hypothalamus of the rabbit, hydrolysed 1.74 +/- 0.11 mu-moles of substrate/min/g and 3.78 +/- 0.60 mu-moles substrate/min/g fresh tissue respectively.7. The concentration of butyrylcholinesterase was about one tenth that of acetylcholinesterase in both tissues.8. Choline acetyltransferase present in the neural lobe and in the hypothalamus synthesized 87 +/- 22 mug ACh/hr/g fresh tissue and 378 +/- 149 mug respectively.
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PMID:Acetylcholine and related enzymes in the neural lobe and anterior hypothalamus of the rabbit. 430 97

Changes in the activity of choline kinase were measured in the cerebellum during development. Early transient increase was found in the enzyme activity just prior to and during birth. This period of increase did not coincide with the periods of transient elevation in ornithine decarboxylase and choline acetyltransferase previously observed in the developing cerebellum. The effects of the naturally occurring polyamines (putrescine, spermidine, and spermine) on choline kinase and choline acetyltransferase activities, and of phosphorylcholine (the product of the reaction catalyzed by choline kinase) on ornithine decarboxylase and choline acetyltransferase activities, were also examined. Choline acetyltransferase activity was not influenced by either polyamines or phosphorylcholine. However, choline kinase activity from 7-day-old, but not from adult, cerebellum was increased 25% in the presence of 4 mM spermine. In contrast, low spermidine concentrations (less than 2 mM) inhibited choline kinase activity selectively in 7-day-old cerebellum. Ornithine decarboxylase activity from 7-day-old cerebellum was inhibited in a concentration-dependent manner by phosphorylcholine. The present data together with other previous reports suggest that: (a) polyamines may play a role in choline utilization during development via their regulation of choline kinase activity, on the one hand, and of acetylcholinesterase activity on the other; and (b) during development, a reciprocal regulation of choline kinase and ornithine decarboxylase activities by their respective reaction products may exist, whereby choline kinase activity is regulated in a complex manner by polyamines and, in turn, ornithine decarboxylase is inhibited by phosphorylcholine.
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PMID:Reciprocal regulation of ornithine decarboxylase and choline kinase activities by their respective reaction products in the developing rat cerebellar cortex. 609 41

d-Amphetamine and amitriptyline (AT) were administered daily to female rats from day 7 of pregnancy until birth of the litters. Changes in the concentration of the biogenic amines, some of their metabolites, GABA, and the activities of glutamate decarboxylase, acetylcholinesterase (AChE), and choline acetyltransferase were determined in the whole brain of the offspring. The offspring of the amphetamine-treated rats showed a marked increase in serotonin concentration and that of its metabolite on postnatal day 1. Changes in the concentration of GABA were apparent on days 15 and 21 and were inversely correlated with changes in the activity of the synthesizing enzyme: Choline acetyltransferase and AChE activities were also increased at this time. Changes in neurotransmitter metabolism were not so evident in the offspring of rats treated with AT. The locomotor activity of the 8-, 15-, and 21-day offspring was also assessed. The offspring of the amphetamine-treated rats showed enhanced locomotor activity initially, but the activity decreased relative to the age-matched controls in the 21-day group. Offspring from the AT-treated group showed reduced locomotor activity.
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PMID:The effect of d-amphetamine and amitriptyline administered to pregnant rats on the locomotor activity and neurotransmitters of the offspring. 612 48

The enzymatic machinery for neurotransmitter synthesis and breakdown have been compared in sister cultures of newborn rat sympathetic neurons grown for 12-28 days either in the presence (CM+ cultures) or in the absence (CM- cultures) of a culture medium conditioned by rat skeletal muscle cells. Neuron numbers, total protein, and lactate dehydrogenase activities were identical in CM+ and CM- cultures. Choline acetyltransferase activity was 27- to 100-fold higher in homogenates of CM+ than CM- cultures, whereas acetylcholinesterase activity was 2.5-fold lower. The activities of tyrosine hydroxylase (TOH), DOPA decarboxylase, and dopamine beta-hydroxylase were all about twofold lower in homogenates from CM+ cultures. All these effects were also observed in homogenates of sympathetic neuron cultures grown with and without a macromolecular factor partially purified from CM (Weber, J. (1981). Biol. Chem. 256, 3447-3453.). Experiments of mixing homogenates from CM+ and CM- cultures suggested that the differences in each of the enzyme activities did not result from differences in the concentrations of hypothetical reversible enzyme activators and/or inhibitors. In addition, the deficit in TOH activity in CM+ cultures resulted from a decrease in the enzymatic Vmax with no significant variation in the apparent Km's for the substrate and the cofactor. An identical decrease in the Vmax was observed if TOH was assayed under phosphorylating or nonphosphorylating conditions, suggesting that this decrease did not result from differences in the state of enzyme phosphorylation. Immunoprecipitation curves of TOH activity by an anti-TOH antiserum were parallel when performed on homogenates from CM+ and CM- cultures, suggesting a difference in the number of enzyme molecules without detectable alteration of their kinetic properties.
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PMID:Regulation of enzymes responsible for neurotransmitter synthesis and degradation in cultured rat sympathetic neurons. I. Effects of muscle-conditioned medium. 613 28

Rats were treated for 2-6 weeks with guanethidine after which their superior cervical ganglia were removed. Ganglionic tyrosine hydroxylase and alpha-bungarotoxin binding sites were reduced by the guanethidine treatment indicating adrenergic cell body destruction. Choline acetyltransferase activity and acetylcholine content of ganglia were not clearly changed by the guanethidine treatment, indicating that the drug does not destroy presynaptic terminals and that these presynaptic indicators do not adapt markedly to postsynaptic loss. The cholinesterase in the ganglia was reduced by guanethidine treatment, but such ganglia retained their ability to accumulate surplus acetylcholine when they were incubated with physostigmine. This is interpreted as indicating surplus acetylcholine accumulation is a presynaptic phenomenon. Choline uptake by resting ganglia was not reduced as a result of guanethidine treatment nor was it affected by preganglionic denervation. This is interpreted as indicating that during rest, choline uptake is into supporting cells or intraganglionic cells rather than cholinergic nerve terminals or adrenergic cell bodies.
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PMID:Effect of chemical destruction of adrenergic neurones on some cholinergic mechanisms in adult rat sympathetic ganglia. 614 15


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