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 the application of a single dichlorvos flea collar containing 500 mg of the insecticide were observed in 23 growing cats for periods of from 1 to 15 weeks. No overt signs of toxicity occurred and weight gain in young growing animals was not significantly affected. Whole blood cholinesterase was reduced within the first week of application of the collar and remained below pretreatment levels for 5 to 8 weeks before returning to normal presumably as the insecticide concentration in the resin was progressively reduced. Signs of systemic organophosphate toxicity did occur within 1 week of the application of three collars to each of two cats kept in the same cage. This suggested that the likelihood of toxicity occurring in cats following the use of dichlorvos flea collars depended mainly on the degree of exposure to the insecticide. Considering recent reports in the literature it was proposed that the environmental conditions of temperature (11 degrees to 23 degrees C) and relative humidity (50 to 65%) under which the experiments were carried out would have promoted a relatively low atmospheric concentration of dichlorvos in the near environment of the test animals and hence generally prevented occurrence of clinical signs. Under most conditions of keeping domestic cats in Australia the use of a single dischlorvos flea collar should therefore be without any untoward effect although some initial and transient inhibition of whole blood and nervous tissue cholinesterases would be expected.
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PMID:Some toxicity aspects of dichlorvos flea collars in cats. 61 29

Several experiments were conducted to test whether, as suggested by Welch et al. in this journal, mere group living (social stimulation) can account for the significant differences in measures of brain anatomy and brain chemistry that develop between rodents housed in groups in enriched environments and rodents housed singly in restricted environments; the alternative hypothesis was that features of the inanimate environment can significantly affect brain measures of animals living in a social group. Groups of 12 male rats were assigned for 30 days to several types of environment: (a) large cage without stimulus objects, (b) large cage containing varied stimulus objects, (c) large cage containing a maze whose pattern of barriers was changed daily, and (d) a seminatural outdoor environment; in each experiment, littermates of rats in the social conditions were housed in isolation in small colony cages. At the end of the 30-day period, measures were taken of weights of brain regions, RNA and DNA contents of regions of cerebral cortex, and acetylcholinesterase activities of brain regions. Although the number of rats housed together was constant for conditions a--d and cage size was constant for conditions a--c, the magnitudes of the cerebral measures varied significantly as a function of the inanimate stimulus conditions. The differences from isola;ion-housed littermates was greatest in condition d and smallest in condition a. Thus, social grouping alone is inadequate to explain the cerebral effects of enriched environments and the inanimate stimulus conditions must be taken into account.
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PMID:Social grouping cannot account for cerebral effects of enriched environments. 69 94

At 31 days of age, Long-Evans female rats sustained aspirative lesions of the septohippocampal pathways and, 14 days later, received intrahippocampal suspension grafts prepared from the region including the medial septum and the diagonal band of Broca (Group S, n = 11), from the region including the mesencephalic raphe (Group R, n = 11) or from both regions together (Group S+R, n = 11). Sham-operated (Group Sham, n = 9) and lesion-only (Group Les, n = 11) rats served as non-grafted controls. Seven Sham, 7 Les and 8 rats from each transplant group were tested for home cage activity (6 months after grafting) and radial maze performance (between 7.5 and 8.5 months post-grafting). One month after completion of behavioral testing, the dorsal hippocampi of these rats were prepared for measuring choline acetyltransferase (ChAT) activity and high affinity synaptosomal uptake of both [3H]choline and [3H]serotonin. The remaining rats were used for histological verifications on brain sections stained for acetylcholinesterase (AChE). The lesions increased locomotor activity, impaired radial maze learning and, in the dorsal hippocampus, reduced AChE positive staining, decreased ChAT activity (-73%) as well as high affinity uptake of both choline (-81%) and serotonin (-82%). Neither type of transplant produced any significant behavioral recovery. However, septal transplants increased hippocampal AChE positivity, restored ChAT activity and enhanced choline uptake to 116% and 70% of the values found in sham-operated rats, respectively; they had no significant effect on uptake of serotonin. Transplants from the raphe region had weak effects on hippocampal AChE positivity, increased both the ChAT activity and the choline uptake to 70% ad 38% of the sham-operated rats, respectively, and produced an (over)compensation of the serotonin uptake which reached 324% of the values found in sham-operated rats. The co-transplantation of both regions resulted in restoration of ChAT activity (113% of sham-operated rats values), choline uptake (83% of sham-operated rats) and serotonin uptake (129% of sham-operated rats). Our neurochemical data show that after extensive denervation of the hippocampus, intrahippocampal grafts of fetal neurons may foster a neurotransmitter-specific recovery which depends upon the anatomical origin of the grafted cells: a graft rich in serotonergic neurons overcompensates the serotonergic deficit, a graft rich in cholinergic neurons attenuates the cholinergic deficit, whereas a mixture of both types of grafts produces recovery from both types of deficits. Thereby, both the feasibility and the interest of the co-grafting technique are confirmed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of septal and/or raphe cell suspension grafts on hippocampal choline acetyltransferase activity, high affinity synaptosomal uptake of choline and serotonin, and behavior in rats with extensive septohippocampal lesions. 151 8

Mite infestation in laboratory mice is a common, but troublesome problem in animal facilities. Recommended treatment regimens are frequently ineffective because of the short period of exposure to the control agent. In an effort to develop a time-release approach, we have investigated the use of Dursban granules applied in animal bedding. Initial toxicity studies indicated that this pesticide can be added to shoebox cage litter at levels three times that used for outdoor application (6 g per 27 by 48 cm shoebox cage) without producing clinical signs of toxicity. Metabolism studies demonstrated that although individual mice showed decreased brain acetylcholinesterase activity following treatment, liver cytosolic glutathione-S-transferase, liver microsomal aminopyrine N-demethylase, or aryl hydrocarbon hydroxylase were not induced after 1 week of exposure. Parasitological studies indicated elimination of mites and itching in an experimental infestation, as well as reduction of itching in severely symptomatic, naturally infested mice, following treatment with the granules. These studies demonstrate the nontoxic efficacy of Dursban in the control of Myobia musculi.
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PMID:The efficacy and safety of chlorpyrifos (Dursban) for control of Myobia musculi infestation in mice. 171 72

Long-Evans female rats sustained electrolytic lesions of the fimbria and the dorsal fornix and, 10-14 days later, received intrahippocampal suspension grafts of septal-diagonal band tissue from either 14-day-old (Group S14, n = 8) or 16-day-old fetuses (Group S16, n = 10), or of parietal cortex from 16-day-old fetuses (Group Cx, n = 10). Sham-operated (Group S, n = 10) and lesion-only (Group Fifo, n = 21) rats served as non-grafted controls. Spontaneous alternation was assessed in a T-maze at three weeks and two months post-grafting. Home cage and open field activity as well as radial maze learning were assessed from two months post-grafting onwards. Fimbria-fornix lesions induced lasting hyperactivity in both the open field and the home cage, impaired radial maze learning and transiently reduced spontaneous alternation rates. Neither type of graft significantly affected home cage activity. Septal-diagonal band grafts improved open field habituation (within trial decline of ambulatory activity) and radial maze learning; the former was observed only in S16 rats, whereas the latter was observed only in S14 rats. Acetylcholinesterase histochemistry revealed an initial lesion-induced depletion of hippocampal acetylcholinesterase (eight days post-surgery) which was no longer observed at the end of the experiment. Acetylcholinesterase positivity was similar in S14 and S16 grafts, which also contained many choline acetyltransferase-positive neurons. Cortical grafts were found to be almost devoid of acetylcholinesterase positivity and no well-stained choline acetyltransferase-positive neurons could be identified. Septal-diagonal band grafts from 14-day-old fetuses and cortical grafts contained more parvalbumin-positive neurons than septal-diagonal band grafts provided by 16-day-old fetuses. These results suggest that grafts rich in cholinergic neurons may promote behavioral recovery from fimbria-fornix lesion-induced deficits. However, such a recovery may concern different behavioral deficits as a function of the age of the implanted tissue, suggesting that the maturity stage of the donor may critically influence the functional expression in the lesioned recipient. Also, such a recovery does not appear to be related solely to cholinergic hippocampal (re)innervation and might depend on the presence, not only of cholinergic neurons, but also of non-cholinergic neuronal populations, such as parvalbumin-positive (probably GABAergic) neurons.
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PMID:Graft-induced behavioral recovery from subcallosal septohippocampal damage in rats depends on maturity stage of donor tissue. 177 34

By means of radioisotope, the daily changes of cholinergic nervous markers, acetylcholine (ACh), choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and muscarinic receptors in the mouse brain were measured in September and October. The mice were housed 5 animals to a cage under natural light-dark cycle (12 : 12) for 7 d in the laboratory room at 18-22 degrees C. The determinations of ACh were taken, every 2 h, to assess the brain ACh of 5 mice for 24 consecutive hours. M-cholinergic receptors, ChAT and AChE activity were examined at 10:00, 16:00 and 22:00. The results demonstrated that the ACh contents, ChAT activity and muscarinic receptor Bmax value were high at 10:00, low at 16:00 and 22:00. However, AChE maximum activity was found at 16:00, minimum activity at 22:00. But the affinity of muscarinic receptors to [3H]QNB did not show any significant daily changes. These data strongly suggested that in mouse brain the cholinergic nervous markers showed a clear daily rhythm.
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PMID:[Circadian changes of acetylcholine, choline acetyltransferase, acetylcholinesterase and muscarinic receptors in mouse brain]. 177 79

Based on three experiments, this study examined whether behavioral and histological effects of fetal septal or hippocampal grafts placed in the denervated hippocampus depend on the duration of post-grafting delays. Each experiment included four groups of rats: sham-operated rats (Sham), rats with aspirative lesions of the fimbria-fornix (Fifo) and rats given both Fifo lesions and intrahippocampal fetal suspension grafts of either septal (Fifo.ST) or hippocampal (Fifo.HT) origin. All rats were tested (i) for home cage activity, (ii) for activity and reactivity in an open field and (iii) for learning ability in a 8-arm radial maze. Except for home cage activity which was also monitored preoperatively, behavioral tests were conducted between 1-2 months postgrafting in Experiment 1 (EXP1), 5-6 months post-grafting in Experiment 2 (EXP2) and 10-11 months post-grafting in Experiment 3 (EXP3). Each test period lasted 3 weeks. Histological controls consisted of acetylcholinesterase (AChE) and cresyl violet staining. Graft size was estimated by computerized image analysis. Normal rats performed well in each experiment. In all experiments, rats with fimbria-fornix lesions showed increased activity in both their familiar (home cage) and unfamiliar (open field) environments, and their performances in the radial maze task were impaired. In no experiment did grafts, whether hippocampal or septal, affect "noncognitive" behavioral variables. However, maze performance was improved by hippocampal grafts in EXP1 (short delay) and by septal grafts in EXP2 (intermediate delay). No graft-induced effect was found in EXP3 (long delay). Concerning AChE-positivity in the dorsal hippocampus, fimbria-fornix lesions reduced staining densities by at least 60%. Both types of grafts were undiscernably AChE-positive, but only septal grafts provided the denervated hippocampus with a significant AChE-positive fiber ingrowth. Differences among groups in density of hippocampal AChE staining were comparable in all three experiments and no correlation between hippocampal AChE-positivity and maze performance was found. Our results suggest that graft-induced recovery from behavioral effects of fimbria-fornix lesions may depend on both the type of tissue implanted (hippocampal vs septal) and the post-grafting delay (1-2, 5-6 and 10-11 months). The recovery observed at a short post-grafting delay with hippocampal grafts and at a longer post-grafting delay with septal grafts was not persistent and concerned only cognitive function as assessed by radial maze performance.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Time-dependent effects of intrahippocampal grafts in rats with fimbria-fornix lesions. 239 24

Stress-induced renin and prolactin secretion was investigated using a conditioned emotional response paradigm. Three minutes after placement in a chamber the rats received an electric shock to their feet via the grid floor, then were immediately returned to their home cage. This procedure was repeated for 3 consecutive days. On the fourth day, instead of receiving an electric shock, they were removed after 3 min and sacrificed by decapitation. Control rats were treated identically with the exception that shock was not administered at any time. There was a significant increase in plasma renin activity and prolactin level in the stressed rats. The administration of the antianxiety drugs chlordiazepoxide (10 mg/kg i.p.) or midazolam (0.125-2 mg/kg i.p.) blocked the stress-induced increase in prolactin levels but not the stress-induced rise in plasma renin activity. Administration of the beta-blocker propranolol (1 mg/kg i.p.) inhibited, but did not completely block, stress-induced rise in plasma-renin activity and had no effect on stress-induced prolactin secretion. The opiate antagonist naloxone (0.1-10 mg/kg i.p.) and the acetylcholinesterase inhibitor diisopropyl fluorophosphate (0.5 mg/kg i.p.) did not block stress-induced renin or prolactin secretion. It is concluded that stress-induced prolactin secretion is regulated by a benzodiazepine-mediated mechanism and that stress-induced renin but not prolactin secretion is mediated in part via beta-receptors.
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PMID:Pharmacological studies on stress-induced renin and prolactin secretion: effects of benzodiazepines, naloxone, propranolol and diisopropyl fluorophosphate. 299 44

The organophosphate pesticide, dichlorvos (DDVP), is used commonly to control ectoparasites in laboratory rodents colonies. This compound is relatively nontoxic to Mus musculus at dosages several times the therapeutic level. However, usage of a similar therapeutic level in the white-footed mouse (Peromyscus leucopus) resulted in substantial mortality. To determine whether P. leucopus is more susceptible than M. musculus to the toxic effects of DDVP, both species were exposed to 0, 3 and 6 g of pelleted DDVP per cage. In a subsequent experiment, P. leucopus were exposed to 0 and 1 g of DDVP per cage. Mortality was not observed in M. musculus at any dosage level. P. leucopus exposed to 1, 3 and 6 g of DDVP exhibited mortalities of 3%, 20% and 53%, respectively. Mean serum cholinesterase in P. leucopus exposed to 3 and 6 g of DDVP was 0.35 and 0.21 U/ml as compared to 3.13 U/ml in unexposed mice. The analogous values for M. musculus were 1.60 and 0.79 U/ml while the level in unexposed mice was 6.79 U/ml. In the second experiment, mean serum cholinesterase in P. leucopus exposed to 1 g of DDVP was 0.32 U/ml as compared to 2.33 U/ml in unexposed mice. Histopathology revealed no lesions in the brain, liver or kidneys. The increased susceptibility of P. leucopus to the toxic effects of DDVP was related to the lowered serum cholinesterase. This indicates that DDVP should not be used for control of ectoparasites in P. leucopus.
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PMID:Dichlorvos toxicity in the white-footed mouse (Peromyscus leucopus). 366

Pregnant CD-1 mice were exposed to 2.45-GHz continuous wave microwave radiation at an incident power density of 30 mW/cm2. The local specific absorption rate near the uterine area (deep colonic location), as determined from time-temperature profiles measured with a Vitek thermistor probe, was 40.2 mW/g. Groups of mice were exposed 8 hr per day through Days 1-6 or 6-15 of pregnancy. Other groups of animals were exposed to an elevated ambient temperature of 31 degrees C which increased the colonic temperature 2.3 degrees C, the same as that produced by the microwaves. Sham-irradiated groups of animals were treated exactly the same as the microwave-exposed animals. For the two conditions, temperature exposed and sham exposed, two groups of animals were used. One group was handled in the same manner as the microwave-irradiated group and the other group was not handled so as to evaluate the effects of stressing the animals by handling. Eleven groups of animals were used in the complete study: five groups for gestational Days 1-6, five groups for gestational Days 6-15, and one group of cage control animals. On Day 18 of gestation the dams of all experimental groups were sacrificed and their reproductive status was determined. The fetuses were examined for visceral and skeletal alterations. Brain cholinesterase activity and histology were evaluated in the groups exposed on Days 6-15. The results show that microwave radiation increases embryo lethality at the early stages of gestation (exposure Days 1-6). Fetal toxicity and teratogenicity were not significantly increased by exposure to microwaves on either Days 1-6 or 6-15 of gestation. Cholinesterase activity and histology of the brain of 18-day-old fetuses were not adversely affected.
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PMID:Teratogenic, biochemical, and histological studies with mice prenatally exposed to 2.45-GHz microwave radiation. 398 69


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