Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electroretinographic changes induced by organophosphorus pesticides (OPs) were studied in rats. Male Wistar rats were intraperitoneally injected with fenthion, chlorpyrifos, fenitrothion, dichlorvos or chlorfenvinphos at doses of 0.01 mmol/kg and/or 0.05 mmol/kg. The electroretinogram (ERG) was recorded at 5 hours and 2 days after the administration, and brain and retinochoroid cholinesterase (ChE) activities was assayed at 3 days after the injections. The brain and retinochoroid ChE activities were reduced in rats treated with the OPs. Notably, the reduction of ChE activities by fenthion, chlorpyrifos and dichlorvos were similar. The administration of OPs induced a change in the ERG, characterized by alteration of the amplitudes of a- and b-waves. Nevertheless the ChE activities in the brain and retinochoroid were inhibited by all of the OPs, the OPs affected the amplitude of ERG differently. Fenthion and chlorpyrifos decreased the amplitudes; dichlorvos and chlorfenvinphos increased; and fenitrothion transiently decreased at 5 hours but increased 2 days after the injection. These results indicate that a factor or factors other than inhibition of ChE activities contributes to the alteration of ERG induced by OPs.
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PMID:Electroretinographic changes induced by organophosphorus pesticides in rats. 169 27

Fenthion, an irreversible cholinesterase inhibitor, was used to study the role of the cholinergic system on the development of gizzard erosion. Fenthion increases the gizzard erosion score in a dose-dependent manner and this effect became significant at levels higher than .1 ppm (p less than .05). An inverse relationship between plasma cholinesterase activity and pesticide concentration was also observed at doses higher than 1 ppm (P less than .05). These results show the necessity to evaluate organophosphate pesticide levels during the selection of fish meals in poultry.
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PMID:Research note: ability of fenthion to increase gizzard erosion in broiler chicks. 188 75

To study the effect of occupational organophosphate exposure on neuromuscular function, 24 workers exposed to fenthion [0,0-dimethyl-0(4-methyl mercapto-3 methyl phenyl)phosphorothioate], whose mean age was 31.7 years (range 22-50) and mean duration of exposure to fenthion 8.5 years (range 1-19) were subjected to detailed clinical and neurophysiological evaluation after spraying. The neurophysiological tests included motor and sensory nerve conduction velocity; F response, H reflex and electromyographic neuromuscular synapse testing. Fenthion exposure was monitored by serum acetyl cholinesterase (AchE) levels. The observations were repeated after withdrawing the workers from fenthion exposure for 3 weeks to study the reversibility of the observed changes. There was no clinical evidence of peripheral neuropathy or muscle weakness. However, peroneal motor conduction velocity (p less than 0.05) terminal motor latency of median (p less than 0.1), and peroneal nerve (p less than 0.05); F minimal latency and H reflex latency (p less than 0.01) were significantly affected. Twenty-nine per cent of workers had repetitive muscle activity. Serum AchE levels also showed significant changes (p less than 0.01). The clinical significance of these subtle neurophysiological changes requires further investigation and follow-up.
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PMID:A study of nerve conduction velocity, late responses and neuromuscular synapse functions in organophosphate workers in India. 319 Apr 48

1. Adult black ducks (Anas rubripes) were given freshwater or saltwater (1.5% NaCl) for 11 days and half of each group was also given an organophosphate (17 p.p.m. fenthion) in the diet on days 6-11. 2. After 11 days, ducks drinking saltwater had lost more weight and had higher plasma Na and uric acid concentrations and osmolalities than birds drinking freshwater. 3. Saltwater treatment stimulated the salt gland to increased weight and Na, K-ATPase activity. 4. Fenthion generally reduced plasma and brain cholinesterase activity and depressed cholinesterase and Na, K-ATPase activities in salt glands of birds drinking saltwater.
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PMID:Organophosphate inhibition of avian salt gland Na, K-ATPase activity. 612 65

Brain and plasma cholinesterase (ChE) activities were determined for mallard ducklings (Anas platyrhynchos) exposed to dicrotophos and fenthion. Recovery rates of brain ChE did not differ between ducklings administered a single oral dose vs. a 2-week dietary dose of these organophosphates. Exposure to the organophosphates, followed by recovery of brain ChE, did not significantly affect the degree of brain ChE inhibition or the recovery of ChE activity at a subsequent exposure. Recovery of brain ChE activity followed the general model Y = a + b(logX) with rapid recovery to about 50% of normal, followed by a slower rate of recovery until normal ChE activity levels were attained. Fenthion and dicrotophos-inhibited brain ChE were only slightly reactivated in vitro by pyridine-2-aldoxime methiodide, which suggested that spontaneous reactivation was not a primary method of recovery of ChE activity. Recovery of brain ChE activity can be modeled for interpretation of sublethal inhibition of brain ChE activities in wild birds following environmental applications of organophosphates. Plasma ChE activity is inferior to brain ChE activity for environmental monitoring, because of its rapid recovery and large degree of variation among individuals.
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PMID:Recovery of brain and plasma cholinesterase activities in ducklings exposed to organophosphorus pesticides. 722 73

Several reports have suggested that exposure to organophosphate pesticides damages the visual system. The prolonged effects of an acute dose of fenthion (dimethyl 3-methyl-4-methylthiophenyl phosphorothionate) were studied on the cholinergic system of the rat retina. Fenthion was administered in a single dose of 0 or 100 mg/kg (sc, in corn oil) to adult, male, Long-Evans rats. The animals were killed 4, 14, or 56 days after treatment and cholinesterase (ChE) activity as well as muscarinic receptor (mChR) function measured in the retina and frontal cortex. Fenthion produced 89% inhibition of ChE activity in both tissues at 4 days, and, although there was recovery, slight (15%) inhibition of the enzyme activity was still observed at 56 days in both tissues. A long-lasting decrease in carbachol-stimulated inositolphosphate (IP) release was observed following fenthion treatment in the retina: IP release was depressed at 4 days and this depression persisted up to 56 days after dosing. The density of mChR in the retina as well as in the cortex was decreased by 14-20% at 4 days and returned to control levels by 56 days. Fenthion had no effect on the metabolism of phospholipids in the retina following intraocular injections of labeled precursors [3H]myo-inositol, [methyl-14C]choline, or [2-3H]glycerol 4 days after fenthion treatment. These prolonged effects of fenthion on mChR function (signal transduction) appear to be specific to the retina as the cortex showed no change in receptor-stimulated IP release even in the presence of significant mChR down-regulation and ChE inhibition. This dose of fenthion did not produce overt morphological changes in the retina or in the cortex, as observed with light microscopy, although an increase in glial fibrillary acidic protein immunoreactivity (GFAP IR) extending from the internal limiting membrane to the external limiting membrane of the retina was noted. This increase in GFAP IR was observed at 14 days and persisted as long as 56 days post-treatment in the retina, but was not noted in the cortex at any of the time points studied. Thus, this long-lasting perturbation in the retinal cholinergic second messenger system induced by fenthion may occur independently of depressed ChE activity and down-regulation of mChR.
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PMID:Fenthion produces a persistent decrease in muscarinic receptor function in the adult rat retina. 817 35

Fenthion and diazinon, P = S type organothiophosphates which are precursors of cholinesterase inhibitors, cause remarkable atropine-insensitive hypotension in rats when administered intravenously in lethal doses. We investigated their effects on isolated rat aorta and atria to reveal the site of action. Fenthion and diazinon inhibited both types of contractions induced by high K+ solution and norepinephrine in aortic preparations from which the endothelium was removed. IC50 values (under [Ca2+] = 1.5 mM) were 2 x 10(-5) M and 7 x 10(-5) M, respectively. However, the atrial preparations were relatively resistant, since fenthion showed no effect up to 10(-3) M and diazinon at 10(-4) M exhibited a slight inhibition which was antagonized by atropine. The hypotensive effect of fenthion or diazinon was therefore attributable to the direct inhibiting action on the arterial muscle tone, which may be independent of the activation of muscarinic receptors. The results suggested that fenthion and diazinon affect movement and/or utilization of calcium in the aortic muscle cells, since an increase in the calcium concentration in the bathing solution antagonized their inhibitory effect.
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PMID:Inhibitory effect of fenthion and diazinon on the contraction of rat aorta, and its contribution to lethality. 835 10

The use of cholinesterase activity as a biochemical method for monitoring organophosphate pesticide exposure in cattle is described herein. Determination of cholinesterase activity of whole blood, erythrocyte, and plasma was carried out according to the Ellman modified kinetic method. The mean baseline acetylcholinesterase activities of 9.549 +/- 3.619 IU/mL in whole blood, 9.444 +/- 3.006 IU/mL in erythrocytes, and 0.149 +/- 0.063 IU/mL in plasma were estimated for steers from the control group. Results of multivariate analysis showed that the general responses between the control and experimental groups (in vivo, monitoring and case studies) treated with Coumaphos and Fenthion were statistically different, and the general responses of these experimental groups were statistically different over time as well. Among the fractions that were analyzed, the erythrocyte acetylcholinesterase activity could be adequate for the diagnosis of exposure or acute poisoning in cattle as it showed a good within-run and between-run precision with CVs <10% better than those in plasma.
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PMID:Use of cholinesterase activity in monitoring organophosphate pesticide exposure of cattle produced in tropical areas. 1174 8

Two cases of severe fenthion intoxication are presented. The first is a case of a psychiatric patient who attempted suicide with ingestion of the compound, and the second case was of a child exposed to the chemical agent by air spraying. Both patients were treated in the intensive care unit with atropine and pralidoxime and finally survived. Fenthion blood levels on admission were 2.7 and 0.95 microg/mL, respectively. Different concentrations of pralidoxime were added to the first patient's poisoned serum in order to assess in vitro the effect of pralidoxime on cholinesterase reactivation. The clinical and toxicological data of the poisonings are discussed, as well as the potential therapeutic use of pralidoxime in organophosphate intoxication.
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PMID:Severe fenthion intoxications due to ingestion and inhalation with survival outcome. 1204 24

The search for substitutes for chlorinated hydrocarbon insecticides has led to the trial of organophosphorus compounds. Fenthion is promising as a residual spray in malaria eradication, but information on its human toxicology is scanty. In the work reported in this paper the inhabitants of a Nigerian village have been studied during a trial of fenthion. Moderate depressions of plasma cholinesterase were observed for five weeks after spraying, though there was no effect on red blood cell cholinesterase. A search was also made for other possible effects, including measurements of peak expiratory flow rate. No serious toxic effects were found.
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PMID:OBSERVATIONS ON HUMAN EXPOSURE TO THE ORGANOPHOSPHORUS INSECTICIDE FENTHION IN NIGERIA. 1405 73


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