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

In order to clarify the role of the amygdala in the working and reference memory of rats in the three-panel runway task, the effects of lesions of subnuclei of the amygdaloid complex on this behavior were studied. Rats that had been trained preoperatively, until they achieved the criterion of learning, were subjected to lesions of the amygdala. In the working memory task, lesions of the basolateral subdivision of the amygdala caused a significant increase in the number of errors (attempts to pass through two incorrect panels of the three panel-gates at four choice points), while lesions of the corticomedial amygdala had no effect on working memory errors. The increase in working errors, observed in basolateral amygdaloid-lesioned rats, declined gradually as retraining sessions were given once each day, reverting to control levels on and after the sixth session. In the reference memory task, the number of errors was not affected by lesions of the basolateral or corticomedial amygdala. The increase in working memory errors, induced by lesions of the basolateral amygdala was significantly reduced by intraperitoneal administration of the inhibitors of cholinesterase, tetrahydroaminoacridine (0.32-1.0 mg/kg) and physostigmine (0.032-0.1 mg/kg), and the muscarinic receptor agonist, oxotremorine (0.1 mg/kg), before the runway test. These findings suggest that the basolateral amygdala is selectively involved in working memory but not in reference memory and that the lowering of central cholinergic function may account for the impairment of working memory, induced by lesions of the basolateral amygdala.
Neuropharmacology 1992 Sep
PMID:Involvement of cholinergic mechanisms in impairment of working memory in rats following basolateral amygdaloid lesions. 143 98

The central cardiovascular effects of a cholinesterase inhibitor, physostigmine, were studied in alpha-chloralose- and urethane-anesthetized cats, to determine the underlying site and mechanism of action. Intravenous injection of physostigmine produced a dose-dependent fall in blood pressure and heart rate. These responses were blocked by intravenous injection of atropine; however, the peripheral antimuscarinic agent, methscopolamine, failed to inhibit the depressor response. In decerebrated cats, physostigmine elicited similar responses in blood pressure and heart rate as in intact animals. In spinal cats, physostigmine failed to evoke any response. Physostigmine significantly reduced sympathetic nervous activity, as measured by renal sympathetic nerve discharges, indicating that the fall in blood pressure was due to a decrease in sympathetic tone. These results demonstrate that physostigmine, which crosses the blood-brain barrier, produces a depressor response through stimulation of muscarinic cholinergic receptors, located in the medullary region and that the effect is mediated by a decrease in sympathetic activity.
Neuropharmacology 1992 Sep
PMID:Central cardiovascular effects of physostigmine in anesthetized cats. 143 99

Heptyl-physostigmine (heptyl-Phy), a new carbamate derivative of physostigmine (Phy), has been assessed for potential clinical value by evaluating its in vitro activity against human erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE), its duration of in vivo activity against rat plasma AChE, and its effects on attenuating a scopolamine-induced impairment in learning performance of young rats in a 14-unit T-maze. Heptyl-Phy demonstrated potent cholinesterase inhibition, with activity similar to that of Phy against AChE, IC50 values 21.7 +/- 2.0 nM and 27.9 +/- 2.4 nM, respectively, and significantly greater than that of Phy against BChE, IC50 values 5.0 +/- 0.1 nM and 16.0 +/- 2.9 nM, respectively. Heptyl-Phy achieved maximum AChE inhibition of 92.5% at 60 min and maintained a high and relatively constant inhibition for more than 8 h. For analysis of effects on learning performance, heptyl-Phy at 1.0, 1.5, 2.0 or 3.0 mg/kg, or vehicle was administered i.p. to 52 3-month-old male Fischer-344 rats 60 min prior to maze training. Thirty minutes prior to training, each animal received either 0.9% NaCl or scopolamine hydrochloride (0.75 mg/kg). Only a 2.0 mg/kg dose of heptyl-Phy significantly reduced the number of errors in scopolamine-treated rats. The other doses did not improve any aspect of maze performance. Although the therapeutic window of heptyl-Phy did not appear wide enough for clinical use, the longer duration of action of heptyl-Phy would appear beneficial.
Neurosci Lett 1992 Sep 14
PMID:The long-acting cholinesterase inhibitor heptyl-physostigmine attenuates the scopolamine-induced learning impairment of rats in a 14-unit T-maze. 143 16

Tetrahydroaminoacridine (THA) and metrifonate are cholinesterase inhibitors used in the treatment of Alzheimer's disease. In experimental animals they inhibit acetylcholinesterase activity and have been reported to increase levels of brain acetylcholine. This paper presents results from studies of their effect at two dose levels on the dynamics of acetylcholine in mouse brain. Metrifonate at two doses (10 and 30 mg/kg intraperitoneally), known to cause cholinesterase inhibition, had no effect on levels of acetylcholine or choline or on the rate of synthesis of acetylcholine. THA (3 mg/kg intraperitoneally) had no effect on levels of acetylcholine and choline but had a shortlasting decreasing effect on the synthesis rate of acetylcholine. THA (10 mg/kg intraperitoneally) increased levels of acetylcholine and choline and markedly decreased the synthesis rate of acetylcholine. At this dose, the animals showed severe cholinergic effects, e.g. tremor and salivation. It is suggested that a moderate cholinesterase inhibition in brain facilitates cholinergic nerve transmission which is obtained at a broader dose range for metrifonate than for THA.
Pharmacol Toxicol 1992 Sep
PMID:Metrifonate and tacrine: a comparative study on their effect on acetylcholine dynamics in mouse brain. 143 50

With prolongation of human age rises also the incidence of senile dementia, inclusive dementia of Alzheimer's type (DAT). At the same time the authors present views in the aetiology of this illness, the role of cholinergic mechanisms of the development dementia and they mention DAT treatment strategy focusing attention on a group of drugs-cholinesterase inhibitors.
Cesk Psychiatr 1992 Sep
PMID:[Present trends in the development of drugs within the cholinesterase inhibitor group as therapeutic agents for Alzheimer's disease]. 145 Dec 5

In determining activities of atypical pseudocholinesterase using a Hitachi 737 and a Cobas Bio analyser, respectively, we repeatedly found discrepancies between the enzyme activities measured by both instruments which were presumably due to differences in the reagent composition (Hitachi 737: Boehringer Mannheim Automated Analysis for BM/Hitachi Systems; Cobas Bio: Boehringer Mannheim Monotest). We consider the present results as a strong hint for manufacturers towards generally declaring all components of the chemical systems they produce and as a warning for users when interchanging apparently identically composed sets of reagents.
Eur J Clin Chem Clin Biochem 1992 Sep
PMID:Influence of reagent composition on atypical pseudocholinesterase activity measurement: comparison of a manual and an automated method and implications for routine. 145 18

Differences in glycosylation of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in human brain, plasma and cerebrospinal fluid (CSF) have been investigated by means of their interaction with agarose-immobilized lectins. Most of the AChE in brain and CSF was associated to concanavalin A (Con A), Lens culinaris (LCA) and Triticum vulgaris (WGA) agglutinins, but little activity was adsorbed to Ricinus communis agglutinin I (RCAI). Brain, plasma and CSF BuChE was almost fully bound to Con A, LCA and WGA-agarose. Brain BuChE was unable to react with RCA (RCA-BuChE), the plasma enzyme was completely bound to the lectin (RCA+BuChE) and BuChE from CSF of normal children was partially fixed to RCA (RCA +/- BuChE). BuChE in CSF of children with meningitis fully reacts with the lectin. The data suggest that the proportion of RCA+BuChE in CSF of children with meningitis is increased, this enzyme probably coming from plasma.
Neurosci Lett 1992 Sep 28
PMID:Ricinus communis agglutinin I reacting and non-reacting butyrylcholinesterase in human cerebrospinal fluid. 146 69

The binding of [3H] quinuclidinyl benzilate (QNB) to rat striatum membranes after diisopropylfluorophosphate (DFP) induced seizures was characterized. There was a 36% decrease in Kd and a 33% decrease in the number of muscarinic receptors. Paraoxon caused inhibition fo [3H] QNB binding to the striatal membranes of intact rats. It is possible that a direct action of DFP on the muscarinic receptor is not the cause of anti-cholinesterase-induced changes in [3H] QNB binding.
Biull Eksp Biol Med 1992 Sep
PMID:[Effects of diisopropylfluorophosphate, paraoxon and dichlophos on [3H] quinuclidinyl benzylate binding to the rat striatum synaptic membranes]. 147 63

Evidence for the involvement of Ser-203, His-447, and Glu-334 in the catalytic triad of human acetylcholinesterase was provided by substitution of these amino acids by alanine residues. Of 20 amino acid positions mutated so far in human acetylcholinesterase (AChE), these three were unique in abolishing detectable enzymatic activity (less than 0.0003 of wild type), yet allowing proper production, folding, and secretion. This is the first biochemical evidence for the involvement of a glutamate in a hydrolase triad (Schrag, J.D., Li, Y., Wu, M., and Cygler, M. (1991) Nature 351, 761-764), supporting the x-ray crystal structure data of the Torpedo californica acetylcholinesterase (Sussman, J.L., Harel, M., Frolow, F., Oefner, C., Goldman, A., Toker, L. and Silman, I. (1991) Science 253, 872-879). Attempts to convert the AChE triad into a Cys-His-Glu or Ser-His-Asp configuration by site-directed mutagenesis did not yield effective AChE activity. Another type of substitution, that of Asp-74 by Gly or Asn, generated an active enzyme with increased resistance to succinylcholine and dibucaine; thus mimicking in an AChE molecule the phenotype of the atypical butyrylcholinesterase natural variant (D70G mutation). Mutations of other carboxylic residues Glu-84, Asp-95, Asp-333, and Asp-349, all conserved among cholinesterases, did not result in detectable alteration in the recombinant AChE, although polypeptide productivity of the D95N mutant was considerably lower. In contrast, complete absence of secreted human AChE polypeptide was observed when Asp-175 or Asp-404 were substituted by Asn. These two aspartates are conserved in the entire cholinesterase/thyroglobulin family and appear to play a role in generating and/or maintaining the folded state of the polypeptide. The x-ray structure of the Torpedo acetylcholinesterase supports this assumption by revealing the participation of these residues in salt bridges between neighboring secondary structure elements.
J Biol Chem 1992 Sep 05
PMID:Mutagenesis of human acetylcholinesterase. Identification of residues involved in catalytic activity and in polypeptide folding. 151 12

Disposition and efficacy of bambuterol were studied in 10 younger (20 to 37 years) and 10 older (69 to 76 years) patients with asthma (nine men and 11 women) at steady state, after single daily doses of 20 mg (50 mumol) for 1 week. There was a greater area under the concentration versus time curve for terbutaline during a dose interval in older patients compared with younger patients (558 +/- 171 and 376 +/- 149 nmol.hr/L, respectively [mean +/- SD], p less than 0.021). This was reflected in a lower apparent plasma terbutaline clearance in older patients compared with younger patients (1.22 +/- 0.33 and 2.32 +/- 1.26 L/hr/kg, respectively, p less than 0.023). Peak drug concentration was not different by age. Plasma cholinesterase levels were depressed by about 70% in both groups compared with pretreatment activity. Peak expiratory flow rate increased in both groups. Improvement in forced expiratory volume in 1 second and forced vital capacity was detected only in the younger patients. A small decrease in heart rate and diastolic blood pressure occurred in both patient groups. Bambuterol appears to offer the possibility of once-daily therapy in both younger and older patients with asthma.
Clin Pharmacol Ther 1992 Sep
PMID:Pharmacokinetics and pharmacodynamics of bambuterol, a long-acting bronchodilator pro-drug of terbutaline, in young and elderly patients with asthma. 152 88


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