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)

1. The negative chronotropic effects of acetylcholine and carbachol on isolated rat right atria were examined at 0, 4, 8, and 16 weeks after birth. 2. Acetylcholine produced negative chronotropic responses at all ages and completely abolished spontaneous beating at its maximum effective concentration. 3. The sensitivity to acetylcholine, expressed in terms of ED50 values, was higher at 0 and 4 weeks than at 8 and 16 weeks, ED50 values (microM) at 0, 4, 8 and 16 weeks being 9.5 +/- 1.8 (n = 12), 13.2 +/- 3.4 (n = 11), 59.3 +/- 10.9 (n = 14) and 51.5 +/- 17.5 (n = 5), respectively. 4. Neostigmine produced a leftward shift of the concentration-response curve for acetylcholine both at 4 and 8 weeks after birth. The shift was larger at 8 weeks and no difference in sensitivity to acetylcholine was observed between the two ages in the presence of neostigmine. 5. Further, no developmental changes were observed in the sensitivity to carbachol, which is not hydrolyzed by cholinesterase. 6. We concluded that the chronotropic sensitivity to acetylcholine of rat atria decreases post-natally during the period between 4 and 8 weeks after birth due to increase in cholinesterase activity.
Gen Pharmacol 1994 Jan
PMID:Post-natal decrease in chronotropic sensitivity to acetylcholine in rat heart. 802 2

AceIJ29 and AceIJ40 are cold- and heat-sensitive variants of the gene coding for acetylcholinesterase in Drosophila melanogaster. In the homozygous condition, these mutations are lethal when animals are raised at restrictive temperatures, i.e., below 23 degrees C for AceIJ29 or above 25 degrees C for AceIJ40. The coding regions of the gene in these mutants were sequenced and mutations changing Ser374 to Phe in AceIJ29 and Pro75 to Leu in AceIJ40 were found. Acetylcholinesterases bearing these mutations were expressed in Xenopus oocytes and we found that these mutations decrease the secretion rate of the protein most probably by affecting its folding. This phenomenon is exacerbated at restrictive temperatures decreasing the amount of secreted acetylcholinesterase below the lethality threshold. In parallel, the substitution of the conserved Asp248 by an Asn residue completely inhibits the activity of the enzyme and its secretion, preventing the correct folding of the protein in a non-conditional manner.
Mol Gen Genet 1994 Jun 15
PMID:Drosophila melanogaster acetylcholinesterase: identification and expression of two mutations responsible for cold- and heat-sensitive phenotypes. 802 87

1. The negative inotropic effects of soman have been reported previously. It was suggested that the depression in atrial force of contraction was a consequence of continuous muscarinic receptor activation by excessive acetylcholine (ACh) accumulation and also possibly through direct interactions at the receptor-associated K+ channels by organophosphate (OP). 2. In this study, the protective effects of tacrine (THA), an antimuscarinic as well as a K+ channel blocker, against soman in guinea-pig atrium were investigated. 3. It was found that tacrine could antagonize the negative inotropic effects of soman. This antagonism occurred in a concentration dependent manner, with effective concentrations (ECs) for tacrine ranging from 1.7 to 12.1 microM when the atrium was equilibrated with 0.05-10 microM soman. 4. Inclusion of an oxime HI-6 (100 microM) in the regimen improved the efficacy of tacrine against soman (1 microM) by 16.1 fold. 5. Addition of a potent antimuscarinic, either atropine or glycopyrrolate with tacrine also improved tacrine's efficacy against soman significantly. 6. Atropine, at equivalent concentration, appeared to be the most effective of the three. At 0.1 microM concentration, atropine was 4.25 and 3.47 times more potent than HI-6 and glycopyrrolate respectively in enhancing THA efficacy. 7. Our results suggested that the immediate suppression of the muscarinic manifestations and the reactivation of the enzyme acetylcholinesterase for the removal of excess ACh are both critical in maintaining the mechanical functions of a heart during acute OP poisoning. The blockade of K+ channels by tacrine may also contribute to countering the depressant effects of soman.
Gen Pharmacol 1993 Nov
PMID:Protection by tacrine and some adjuncts against the depressant effects of soman in guinea-pig atrium. 811 29

The distribution of cholinesterase (ChE) activity was demonstrated in the hypothalamo-hypophyseal system of Heteropneustes fossilis using acetylthiocholine iodide as the substrate. Perikarya of neurons in nucleus lateralis tuberis and the periventricular region of the infundibular recess showed moderate to strong enzyme activity. In the midventral floor of the infundibular recess, the ependymal layer contained ChE-positive neurons, some of which contacted the ventricle. From these neurons, fine beaded axonal processes were seen to run across the fibrous layer close to ChE-positive capillaries. The blood vessels and capillaries in the external palisade layer also showed intense enzyme activity. The distributional pattern of ChE strongly suggests homology of the region with the median eminence of tetrapods. In the pituitary, the neurohypophysis was generally free of enzyme activity except for some displaced neurons, pituicytes, and capillaries. The hypophyseal blood vessels and capillaries showed strong enzyme activity which varied regionally.
Gen Comp Endocrinol 1994 Jan
PMID:Histochemical distribution of cholinesterase activity in the hypothalamo-hypophyseal system of the catfish, Heteropneustes fossilis. 813 9

1. The present study investigated the effects of tacrine (an inhibitor of acetylcholinesterase) and zacopride (the antagonist of 5-HT3 receptors) on the performance of adult rats in a continuous operant delayed non-matching to position task assessing spatial working memory. 2. Adult rats had a decline in the percent correct responses at the longest delays (16 and 30 sec) in this task. Tacrine (1.0 mg/kg) or zacopride (0.0025, 0.05, 1.0 mg/kg) did not increase the percent correct responses at any time delays. The higher dose of tacrine reduced behavioural activity (e.g. the decreased number of trials completed and increased sample press latency) of rats during memory testing, and it slightly increased choice accuracy across all the delays. 3. The combination of zacopride (1.0 mg/kg) and tacrine (1.0 mg/kg) increased the percent correct responses at the shortest delays, but not at the longest delays. 4. These results indicate a non-mnemonic improvement in the accuracy performance of rats, and they suggest that the effects of acute, systemic administrations of zacopride (which is thought to increase the release of acetylcholine) or/and tacrine (which inhibits the breakdown of acetylcholine) do not improve spatial working/short-term memory in rats.
Gen Pharmacol 1993 May
PMID:The effects of tacrine and zacopride on the performance of adult rats in the working memory task. 836 50

1. Clinical and experimental evidence suggest that changes in the autonomic tone play a role in the pathogenesis of atrial fibrillation. 2. We have studied the distribution of molecular forms of acetylcholinesterase (AChE) in atrial biopsies obtained from individuals without arrhythmias and in patients with atrial fibrillation. 3. Analysis of the distribution of globular and asymmetric AChE forms, showed a decrease in the amount of the globular forms of biopsies taken from atria during fibrillation. 4. This study is the first attempt to characterize the molecular forms of AChE in the human heart of patients with sinus rhythm and chronic atrial fibrillation.
Gen Pharmacol 1993 Jan
PMID:Acetylcholinesterase changes in hearts with sinus rhythm and atrial fibrillation. 848 84

1. The present study was designed to examine the effects of intracerebroventricular injection of several cholinergic drugs on the impairment of spontaneous alternation performance induced by the M1-selective muscarinic receptor antagonist pirenzepine. 2. Pirenzepine (3 and 10 micrograms) significantly reduced spontaneous alteration performance related to working memory without producing any marked increase in total arm entries, which are considered to reflect locomotor activity. 3. Physostigmine (3.47 micrograms), a cholinesterase inhibitor, and McN-A-343 (20 micrograms), and M1-selective muscarinic receptor agonist, significantly improved the pirenzepine (3 micrograms)-induced impairment of spontaneous alternation performance, although oxotremorine (0.68 microgram), a nonselective muscarinic receptor agonist, showed a tendency to reverse the pirenzepine (3 micrograms)-induced impairment. 4. These findings suggest that the blockade of muscarinic M1 but not M2 receptors results in the impairment of spontaneous alternation performance associated with working memory.
Gen Pharmacol 1995 Nov
PMID:Cholinergic receptor agonists inhibit pirenzepine-induced dysfunction of spontaneous alternation performance in the mouse. 869 Feb 40

The neurotrophic effects of ebiratide, an ACTH4-9 analog, have been examined using both fetal rat septal cultures and aged rats. The 5-day treatment with ebiratide (10-100 pmol/ml) partially prevented neuronal degeneration that occurred in the cultures in which cells were sparsely plated. Ebiratide (10 pmol/ ml) increased choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities up to 1.5 and 1.2 times the respective control values in the sub-confluent cultures. AChE cytochemistry of the cultures has shown that ebiratide increased the stained area per cell. Ebiratide subcutaneously administered by constant infusion (10 nmol/body/hr) for 4 weeks elevated ChAT activities in the septum (35% over control), neocortex (79%) and hippocampus (89%) of aged rats. Thus, the present study indicates that ebiratide shares neurotrophic properties which may prove beneficial in the therapy for CNS degenerative disorders, especially Alzheimer's disease.
J Neural Transm Gen Sect 1995
PMID:The neurotrophic effects of ebiratide, an analog of ACTH4-9, on cultured septal cells and aged rats. 874 59

The neurons of the caudal neurosecretory system of teleosts contain, in addition to urotensin I and urotensin II, a high concentration of acetylcholine (T. Ichikawa, 1978, Gen. Comp. Endocrinol. 35, 226-233). The isolated urophysis (and attached terminal spinal cord region) of the rainbow trout Oncorhynchus mykiss was incubated with [3H]choline (0.2 MBq/ml) for 45 min at 22 degrees in the presence of the cholinesterase inhibitor, physostigmine. Unreacted choline was removed by perifusion with fish Ringer solution. Incorporation of radioactivity into newly synthesized [3H]acetylcholine was 4.9 +/- 2.1 x 10(5) Bq/g wet tissue wt. When incubations were carried out in the presence of hemicholinium-3, an inhibitor of high-affinity choline uptake, or when physostigmine was omitted from the incubation buffer and/or when [3H]inulin was substituted for [3H]choline, the incorporation of radioactivity was greatly reduced (< 0.5 x 10(5) Bq/g). The release of [3H]acetylcholine from the preparation increased to 338 +/- 59% of basal (P < 0.05) when the concentration of K+ in the perifusion buffer was raised to 41 mM, but neither urotensin I (10(-7) M) nor urotensin II (10(-6) M) had a significant effect on release. The data indicate that the trout caudal neurosecretory system possesses a high-affinity uptake system for choline and that newly synthesized acetylcholine is released in response to a depolarizing stimulus.
Gen Comp Endocrinol 1996 Jul
PMID:Synthesis and release of acetylcholine by the isolated perifused trout caudal neurosecretory system. 881 28

The effects of short-term food deprivation and photoperiod on plasma thyroid hormone levels of sea bass and sea bream were studied. Animals were acclimated under constant photoperiod regime (15L/9D) and feeding times (2 hr after light onset and 2 hr before light offset). Time-course studies involved monitoring plasma hormone levels every 4 hr throughout 1.5 24-hr cycles. Plasma 3,5, 3'-Triiodo-L-thyronine (T3) and L-thyroxine (T4) were assayed using a newly developed competitive enzyme immunoassay, utilizing acetylcholinesterase as a label of enzymatic tracers. Enzyme immunoassays had sensitivities of 1.25-0.02 and 62.5-0.2 ng/ml for T3 and T4, respectively, and reproducibilities of 3.7 and 5.6% intraassay variation for T3 and T4, respectively; interassay variations for T3 and T4 assays respectively were 1.6%, 11% and 6.6%, 8% for sea bass and sea bream plasma similar to RIA. In sea bass, 3 days of food deprivation resulted in depressed plasma T3 and T4, overriding significant diel variations seen during the second day of starvation. Sea bream displayed a slight decrease of T4 plasma levels while T3 levels remained constant for the whole sampling period. Both thyroidal systems responded to photoperiod with a significant increase in plasma T4 level at the time of light onset. In addition, sea bass also displayed increased T3 levels and decreases in both hormone levels coinciding with "lightoff." Data show different responses of the sea bass and sea bream thyroidal systems to both nutritional state and photoperiod in that the latter state is influenced by the former. Data suggest plasma thyroid levels can be used as a rapid indicator of nutritional status.
Gen Comp Endocrinol 1996 Sep
PMID:Development of enzyme immunoassays for 3,5,3'-triiodo-L-thyronine and L-thyroxine: time-course studies on the effect of food deprivation on plasma thyroid hormones in two marine teleosts, sea bass (Dicentrarchus labrax L.) and sea bream (Sparus aurata L.). 881 99


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