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)

The effects of ethanol, 0.1 to 1.0 M, on synaptic transmission, preganglionic axonal fibers and the ganglion cell were examined by extracellular and intracellular recording in isolated bullfrog sympathetic ganglia. Within the concentration range 0.2 to 0.8 M ethanol caused stimulus-bound repetitive postganglionic responses (SBR) to single preganglionic stimuli. The presynaptic origin of ethanol-induced SBR was confirmed by recordings of repetitive synaptic potential responses to single stimuli, and by absence of repetitive responses in myelinated preganglionic axons and in ganglion cells stimulated antidromically. Ethanol acted synergistically with Cs+ to produce SBR more intense than that caused by either agent alone. The postganglionic SBR caused by ethanol was suppressed by concentrations of d-tubocurarine, lidocaine, or tetraethylammonium that had little or no effect on synaptic transmission. Ethanol also blocked synaptic transmission, but this occurred secondary to the initial excitatory effects, and in the concentration range 0.4 to 1.0 M. The present data, together with previous studies of ethanol at neuromuscular junction, indicate that synaptic excitatory effects of ethanol are unrelated to hyperosmolarity or cholinesterase inhibition and represent a primary action of ethanol on prejunctional nerve endings.
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PMID:Stimulus-bound repetitive synaptic firing caused by ethanol in sympathetic ganglion. 30 Jan 5

1. Depending on the hydrophobicity and the site specificity of an inhibitor, striking differences were found in ethanol-acetylcholinesterase (AChE)-inhibitor interactions. 2. AChE used was from electric eel and was purified by affinity chromatography. 3. Ethanol at 10-200 mM reduced the inhibitory ability of tetrabutylammonium bromide (Bu4NBr). 4. The observed reduction might be a result of Bu4NBr inhibition being partially compensated for by an ethanol activation effect. 5. In contrast to Bu4NBr, propidium and edrophonium are not involved in hydrophobic interaction with AChE. 6. Their abilities to inhibit AChE activity were enhanced by ethanol. 7. Such an enhancement could not result from combining individual perturbations from ethanol and propidium or edrophonium, since ethanol itself increased the AChE activity. 8. In the presence of ethanol, propidium which binds to the peripheral site of the enzyme remained as an uncompetitive inhibitor, while edrophonium which binds to the active site was changed from a competitive inhibitor to a mixed one. 9. The effect of ethanol was therefore greater in the inhibitor which is involved with the active-site binding. 10. Fluorescence quenching studies of propidium-bound enzyme and edrophonium-bound enzyme revealed that ethanol in the concentration less than or equal to 400 mM did not cause significant conformational change at both the peripheral and the active sites of the enzyme.
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PMID:Ethanol-acetylcholinesterase-inhibitor interactions: inhibitor hydrophobicity and site specificity dependence. 178 55

1. Biochemical studies of the actions of ethanol on the activity of acetylcholinesterase (AChE), isolated from electric eel (Electrophorus electricus) and purified by affinity chromatography, were performed to elucidate ethanol-enzyme-solvent interactions. 2. Ethanol at a low concentration [( EtOH] = 2.7-200 mM) was found to enhance AChE activity slightly and systematically. 3. This observation was consistent with the result from enzyme-kinetic studies that ethanol might noncompetitively activate AChE activity at this lower concentration range. 4. If ethanol alters the hydrophobic site interaction on the enzyme and subsequently induces a favorable conformation for the active center of the enzyme, then a slight increase in the AChE activity in the presence of a low concentration of ethanol will be observed. 5. This speculation was supported by the finding of ethanol's ability to perturb the inhibition of AChE activity by tetrabutylammonium bromide and to affect hydrophobic interaction between this salt and AChE, as investigated by enzyme activity and microcalorimetric measurements. 6. The ethanol effect on the activity of this soluble AChE was found to be distinguishable from that on a membrane-bound AChE. 7. Furthermore, to elucidate the effect of ethanol-solvent interaction on AChE activity, enzyme activity in the presence of much higher concentrations of ethanol was also examined. 8. At [EtOH] greater than 800 mM, ethanol can perturb the structure of water around hydrophobic areas of AChE, causing an instability in the enzyme conformation and subsequently decreasing AChE activity.
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PMID:Biochemical studies of the actions of ethanol on acetylcholinesterase activity: ethanol-enzyme-solvent interaction. 199 62

The present study investigated differences in cholinergic function which might contribute to genetic differences in the effects of ethanol on inbred mice. Choline acetyltransferase (ChAT), acetylcholinesterase (AChE) activity and [3H]-quinuclidinyl benzilate (QNB) binding were assessed in several brain areas after administration of ethanol (4.6 g/Kg). ChAT in striatum and septum of C57BL/6 mouse strain exhibit greater sensitivity to ethanol as compared to BALB/c mouse strain. While BALB/c limbic system and related structures showed greater sensitivity to ethanol as compared to C57BL/6 strain. Our previous studies indicated that acute ethanol administration in C57BL/6 mice increased striatal ChAT activity (up to 22% with 60 min latency, Durkin et al., 1982). This augmentation in ChAT activity induced by ethanol was associated with non-synchronous decreases in kinetic characteristics of QNB binding in striatum. In contrast, no such changes were seen in BALB/c striatum (except we noted an increase in Kd up to 90 min after acute ethanol treatment). Similar significant increases in ChAT activity were also observed in C57BL/6 septum 165 min after ethanol administration. However, the septum in BALB/c mice did not exhibit comparable changes. Ethanol did increase ChAT activity in several brain areas of both strains. The areas included the hippocampus, temporal limbic cortex and piriform cortex or paleocortex. Interestingly, the latencies to increased ChAT activity in these areas were much shorter in BALB/c than in C57 mice. The kinetic characteristics of QNB binding sites (Bmax and Kd) and AChE activity were unchanged in all brain areas and did not differ by strain except as otherwise indicated. These data indicate that genetic differences in ethanol preference and sensitivity in these strains are accompanied by differential sensitivity of ChAT to acute ethanol. Genotypic variations in dopaminergiccholinergic interactions in striatum and hippocampus (Durkin et al., 1983), and septum (Kempf et al., 1985), temporal limbic and piriform cortex, could contribute to genetic differences in cholinergic sensitivity to ethanol. In addition, different blood-brain barrier and membrane properties might also contribute to genetic differences in the sensitivity of cholinergic function to ethanol. The differential effects on ChAT activity might participate in genetic differences in memory disorders (limbic system and related structures) and motor incoordination (basal ganglia) following high dose alcohol administration.
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PMID:Genetically-determined responses of central cholinergic markers: the effects of ethanol on inbred strains of mice. 262 17

Male and female rat pups were administered ethanol (3 g/kg/dose) twice daily by intragastric intubation between postnatal Day (PN) 4 and 8. Pups were maternally reared throughout the exposure period and until sacrifice on PN20. The consequences of this growth spurt exposure to ethanol were measured by an impact upon body growth, as well as upon specific growth parameters and cholinergic neurochemical factors within the cerebral cortex and corpus striatum. Specific endpoints included muscarinic receptor binding dynamics, acetylcholinesterase (AChE) and choline acetyltransferase (CAT) activities, regional wet weights, and subcellular protein content. In male pups, ethanol resulted in a significant enhancement of body weight gain and an increase in striatal but not cortical mass. Additionally, ethanol exposure resulted in a significant increase in striatal muscarinic receptor affinity, regardless of gender. This was accompanied by evidence of a significantly greater density of striatal muscarinic receptors in males versus females, regardless of treatment. Overall, the ethanol-associated effects are suggestive of a drug-induced developmental delay. Gender-specific, treatment-independent differences were also detected in the developing brain regions. Thus, regardless of treatment, cerebral cortical S1-level protein content was found to be significantly greater in males than in females. Furthermore, there were gender-based, significant differences in AChE activity within the striatum of control pups (males greater than females). Ethanol exposure resulted in a loss of this gender-based difference. We conclude that the cholinergic neurochemical development occurring in the striatum of the female rat brain between PN4 and 8 is exquisitely sensitive to ethanol-induced developmental delays which are not remediable by 12 subsequent days of maternal rearing in the absence of ethanol exposure.
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PMID:Exposure of rats to ethanol from postnatal days 4 to 8: alterations of cholinergic neurochemistry in the cerebral cortex and corpus striatum at day 20. 264 73

Neuronal membrane enzyme activities were determined in naive and ethanol-treated (30 min after 2 g/kg) male and female rats of lines developed for more (ANT) and less (AT) ethanol-induced motor impairment. Ethanol did not affect acetylcholinesterase, (Na+K)-ATPase or 5'-nucleotidase activities, but adenylate cyclase activities were lowered in both cerebellum and cerebrum. Cerebral acetylcholinesterase activities were higher in ANT than AT rats. No consistent line difference was observed regarding (Na+K)-ATPase activities. Slightly higher cerebellar 5'-nucleotidase activities were found in the ANT line. Cerebellar adenylate cyclase levels were substantially higher in the AT line. No line differences were displayed in the activation of adenylate cyclase activity by dopamine or norepinephrine. It is concluded that ethanol in vivo may inhibit neuronal adenylate cyclase activity and that cerebellar phosphorylation may be a regulator of motor impairment. Cholinergic mechanisms may also be connected to the ethanol-induced motor impairment.
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PMID:Neuronal membrane enzymes in rat lines selected for differential motor impairment by ethanol. 301 92

Ethanol was administered chronically to adult rats in a liquid diet for 14 days preceding and for 5, 7, 8, 9, or 10 days following the unilateral destruction of the entorhinal cortex. Control groups received a diet of lab chow and water and were sacrificed at comparable survival times. An additional experimental group was given ethanol until 9 days after the lesion, then switched to lab chow and water and sacrificed 1 day later. Coronal sections through the dorsal hippocampal formation were stained and analyzed histochemically for the localization of acetylcholinesterase (AChE). Quantitative measurements of the histochemical patterns in the molecular layer of the dentate gyrus were obtained. Ethanol exposure inhibited the withdrawal of the acetylcholinesterase-stained septohippocampal fibers and limited the typical lesion-induced expansion of the pale-staining commissural/associational zone in the molecular layer of the denervated dentate gyrus. However, abstinence from ethanol for just 24 h released the inhibitory effect on the acetylcholinesterase-staining fibers, resulting in a significant expansion of the commissural/associational zone.
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PMID:Time course and reversibility of ethanol's suppressive effects on axon sprouting in the dentate gyrus of the adult rat. 304 76

Sodium chloride, phosphate buffer and ethanol were studied for their effect on butyryl cholinesterase hydrolysis rate of acetylcholine, acetylthiocholine, butyrylthiocholine and nonion substrate of indophenylacetate. The concentrations of 1.10(-2) = 1.10(-1) M of sodium chloride activated enzymatic hydrolysis of ion substrates at the concentrations lower than 1.10(-4) M but sodium chloride is a competitive inhibitor at higher concentrations. Phosphate buffer also activates substrates enzyme hydrolysis at the concentrations of 2.10(-4) M and lower, but it inhibits incompetitively the nonion substrate indophenylacetate hydrolysis. Ethanol activates butyrylthiocholine hydrolysis and is a competitive inhibitor in acetylthiocholine and indophenylacetate hydrolysis. The observed effects are discussed on the assumption of two forms of butyrylcholinesterase E' and E" existence. These two forms are determined by different kinetic parameters and are in equilibrium.
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PMID:[Effect of salt composition of the medium and ethanol on cholinesterase hydrolysis of various substrates]. 318 54

We examined the effect of ethanol on lesion-induced sprouting in the molecular layer of the dentate gyrus. Adult rats were fed a liquid diet containing either ethanol or sucrose for 14 days before and 9 days following unilateral entorhinal cortex lesions. One group was provided the ethanol diet ad libitum during both the pre- and postlesion period. Three other groups were pair-fed to the latter group; one consumed ethanol prelesion, one postlesion, and one did not receive ethanol. Sections through the rostral hippocampus were stained for histochemical localization of acetylcholinesterase. Following the entorhinal lesion the pale-staining commissural/associational zone ipsilateral to the lesion typically expands and exhibits decreased acetylcholinesterase staining. When ethanol was administered after the lesion, expansion of the commissural/associational zone was significantly diminished compared with the two groups that received the control diet after the lesion. Ethanol administered for 2 weeks before the lesion had no measurable effect on commissural/associational zone expansion. These findings imply that, at least for short-term exposure, ethanol reduces the sprouting responsiveness of systems in the dentate gyrus only during the postlesion period when sprouting normally occurs.
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PMID:Sprouting responsiveness in the dentate gyrus is reduced by ethanol administered following but not preceding an entorhinal lesion. 362 2

The effects of ethanol on the activities of five membrane bound enzymes were determined using a crude membrane preparation obtained from cortex of long-sleep (LS) and short-sleep (SS) mice. These two mouse lines were selectively bred for differences in duration of ethanol-induced sleep time. The enzymes studied were two forms of NaK-ATPase, Mg-ATPase, 5'nucleotidase, and acetylcholinesterase. Arrhenius plots of the ethanol-temperature-enzyme activity studies indicate specificity in ethanol's actions. NaK-ATPase activity consists of two enzymes which were distinguished by sensitivity to ouabain. The Arrhenius plot of the high ouabain sensitivity enzyme (low Ki) exhibited a transition temperature which was reduced twice as much by ethanol in LS membranes as in SS membranes. Ethanol did not affect the transition temperature of the high Ki NaK-ATPase but the control (no ethanol) transition temperature was 2.7 degrees higher in SS membranes. Arrhenius plots of Mg-ATPase activity did not exhibit a transition temperature and ethanol did not alter enzyme activity. Ethanol did not alter the transition temperatures of 5'nucleotidase or acetylcholinesterase but the control transition temperature for acetylcholinesterase was 2.3 degrees higher in SS membranes. These results indicate specificity in ethanol's actions on membranes and that inhibition of the lipid-enzyme interactions for the low Ki NaK-ATPase is correlated with the difference in sensitivity to ethanol seen between the LS and SS mice.
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PMID:Ethanol and temperature effects on five membrane bound enzymes. 615 1


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