Pseudocholinesterase Activity Research Articles

Pulmonary toxicity of the insecticide fenitrothion in the rat following a single field exposure.

The pulmonary toxicity of the organophosphorus insecticide fenitrothion was evaluated following a single exposure of rats to the field formulation, at the site of an aerial spraying. Four groups of 40 Sprague-Dawley rats (including a control), set in wood enclosures, were placed under the aerial lines of the spraying aircraft. The degree of exposure was monitored at the ground level by air sampling and visual evidence of droplet activity deposition. Plasma pseudocholinesterase activity and pulmonary alveoli ultrastructure were used as indices to the fenitrothion exposure. Rat lungs were examined under light and electron microscopy at days 3, 7, 21, 60 and 180 after the exposure. Although a few signs of toxic lung injury were observed at days 3 and 7 there was no cholinergic crisis nor an effect on the pseudocholinesterase activity within 12 h in the exposed animals, when compared with controls. The alveolar toxic reaction was limited to small and discrete foci, and was entirely reversible within a period of 2 months. On a morphological basis it is thus concluded that a single field exposure to fenitrothion did not induce any permanent change in the alveolar area of the rat lung.

The effect of furazolidone on some clinical and biochemical parameters in goats.

Furazolidone (FZ) administered to goats orally at the recommended therapeutic dose (10 mg/kg body weight for 5 days) resulted in significant decreases in heart rate, pulse rate, and rectal temperature. No change was observed in respiratory rate or body weight, although a tendency towards a decrease in the latter was observed. An increase in the number of the erythrocytes was found. FZ also produced significant decreases in the pseudocholinesterase activity and plasma concentrations of total protein and ascorbic acid. A significant increase in the adrenal cholesterol concentration was observed while the weight of adrenal glands and their ascorbic acid concentration and content were unaffected. No significant histopathological changes were observed in treated goats.

Acetylcholinesterase activity in cerebrospinal fluid of patients with Alzheimer's disease and senile dementia

Acetylcholinesterase (AChE) in the cerebrospinal fluid (CSF) from patients with Alzheimer-type dementia and control subjects was analyzed by centrifugation on a sucrose density gradient, and by column chromatography on Sephadex G-200. The sedimentation coefficient and molecular weight of CSF AChE were calculated as 10S and 380 000, respectively, which corresponded to those of G4 isozyme in the brain. Other isozymes of AChE were not detected in the CSF of either patients with Alzheimer-type dementia or the controls. Sufficient activity of AChE was observed in the CSF of a patient with familial pseudocholinesterase deficiency, although the pseudocholinesterase activity was not found either in the serum or in the CSF. CSF AChE activity in control subjects increased with advancing age ( P < 0.02). AChE activity in the CSF was significantly lower in patients with presenile dementia (Alzheimer's disease), compared with age-matched control subjects ( P < 0.001). However, AChE activity in the CSF showed a wide variation among patients of Alzheimer-type dementia with a late onset (senile dementia).

Pseudocholinesterase Activity and Atracurium V. Suxamethonium Block

Serum pseudocholinesterase activity in pregnant women was assayed spectrophotometrically using either propionylthiocholine or suxamethonium as substrate. All patients had a normal phenotype as indicated by normal dibucaine and fluoride numbers. However, the mean cholinesterase activity was lower than in the general population. There was a negative correlation between cholinesterase activity and the duration of neuromuscular blockade following suxamethonium, but no correlation was observed between the cholinesterase activity and the duration of block following atracurium.

Divergent regulation of muscarinic binding sites and acetylcholinesterase in discrete regions of the developing human fetal brain.

The expression of muscarinic acetylcholine binding sites and of cholinesterases was studied in extracts prepared from discrete regions of the human fetal brain, between the gestational ages of 14 and 24 weeks. The specific binding of [3H]N-methyl-4-piperidyl benzilate [( 4H]-4NMPB) to muscarinic binding sites ranged between 0.05 and 1.30 pmol/mg protein in the different brain regions, with Kd values of 1.2 +/- 0.2 nM. Binding of the cholinergic agonist oxotremorine fitted, in most of the brain regions examined, with a two-site model for the muscarinic binding sites. The density of muscarinic binding sites increased with development in most regions, with different rates and onset times. It was higher by about sixfold in some areas destined to become cholinergic, such as the cortex and midbrain, than in noncholinergic areas such as the cerebellum. In other areas destined to become cholinergic, such as the hippocampus and the caudate putamen, the receptor density remained low. Average density values increased from 0.1 +/- 0.1 at 14 weeks up to 0.7 +/- 0.4 pmol/mg protein at 24 weeks. The variability in the specific activities of cholinesterase was relatively low, and extracts from different brain regions hydrolyzed from 5 to 30 nmol of [3H]acetylcholine/min/mg protein. These were mostly "true" acetylcholinesterase (EC 3.1.1.7) activities, inhibited by 10(-5) M BW284C51, with minor pseudocholinesterase (EC 3.1.1.8) activities, inhibited by 10(-5) M iso-OMPA. The enzyme from different brain regions and developmental stages displayed similar Km values toward [3H]acetylcholine (ca. 4 X 10(-4) M-1). The ontogenetic changes in cholinesterase specific activities had no unifying pattern and/or relationship to the cholinergic nature of the various brain areas. In most of the brain regions, the arbitrary ratio between the specific activity of cholinesterase and the density of muscarinic binding sites decreased with development, with average values and variability ranges of 83 +/- 50 and 19 +/- 19 at 14 and 24 weeks, respectively. Our findings suggest divergent regulation for cholinergic binding sites and cholinesterase in the fetal human brain and imply that the expression of muscarinic receptors is related to the development of cholinergic transmission, while acetylcholinesterase is also involved in other functions in the fetal human brain.

Levels of serum lipids, apolipoproteins A-I and B and pseudocholinesterase activity and their discriminative values in patients with coronary by-pass operation

Serum lipids and apoproteins A-I and B were measured in 115 male patients and serum pseudocholinesterase activity (PChE) was determined in 83 patients with 3 vessel coronary artery disease (CAD). The control subjects were matched according to sex, smoking, relative weight and age and were free from heart disease. The CAD patients had significantly higher serum VLDL cholesterol and triglyceride levels and lower HDL cholesterol and apo A-1 levels and lower HDL to total cholesterol ratio than the controls. The concentrations of serum total cholesterol and LDL cholesterol were only slightly (6.4% and 8.8%, on an average) higher in CAD patients than in controls. The apo B levels of CAD patients were also slightly lower in patients than in controls. The CAD patients had slightly higher PChE activities than controls. The ratios of apo A-I to PChE and HDL cholesterol to PChE were significantly (about 30%, P < 0.001) lower in patients than in controls. In discriminant analysis between the groups HDL cholesterol and apo A-I showed the best (74% success in reclassifying the patients to correct groups), and total cholesterol, triglycerides, LDL cholesterol and apo B remarkably weak discriminating power among the single variables of serum lipids and lipoproteins. In discriminating analysis the apo A-I/PChE and HDL cholesterol/PChE ratios showed relatively high (77.1 and 71.1% success from the patients to correct groups) and serum PChE activity weak discriminating power. These results indicate that low levels of HDL cholesterol and apo A-I and the low ratio of HDL cholesterol to total cholesterol are the most potent metabolic risk factors for 3 vessel coronary artery disease in a population with relatively high serum total cholesterol level. The determinations of apo A-I/PChE and HDL cholesterol/PChE ratios may be an additional, valuable tool in discriminating the risk for CAD.

Early phenobarbital-induced alterations in hippocampal acetylcholinesterase activity and behavior

Early exposure to phenobarbital (PhB) causes marked destruction of large neurons which are then forming both in the hippocampus and in the cerebellum. Such exposure to PhB also reduces the achievements of mice in hippocampus-related behaviors such as radial 8-arm maze performance. Experimental evidence suggests that these behaviors are partially mediated by cholinergic transmission. We studied the performance of mice, exposed to PhB prenatally or neonatally, in radial 8-arm maze. Both treatments caused significant impairments in the animals' performance in the maze. Acetylcholinesterase (AChE) and pseudocholinesterase (pChE) activities were studied in the hippocampus and cerebellum of mice who were exposed to PhB prenatally or neonatally. These enzymes are involved both in cholinergic transmission and in neuronal development. A significant decrease (13-16%, P less than 0.01) in hippocampal AChE specific activity was found between days 15 and 22 in animals exposed to PhB neonatally. The total hippocampal activity of AChE was also greatly reduced (25-39%, P less than 0.01) during that period as a result of both the reduction in specific activity and a reduction in hippocampal weight of the treated animals. These alterations were transient and were not detected in adulthood. No changes in hippocampal AChE or pChE activities were found in animals treated prenatally. Cerebellar AChE and pChE activities were not altered after prenatal nor after neonatal exposure to PhB. It is possible that the short-term effect of neonatal treatment on AChE specific activity might mediate the long-term impairments in hippocampus-related behaviors.

Polymorphism of acetylcholinesterase in discrete regions of the developing human fetal brain.

The molecular forms and membrane association of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) and pseudocholinesterase (acylcholine acylhydrolase, EC 3.1.1.8) were determined in the presence of protease inhibitors in dissected regions of developing human fetal brain, as compared with parallel areas from mature brain. All areas contained substantial cholinesterase activities, of which acetylcholinesterase accounted for almost all the activity. Two major forms of acetylcholinesterase activity, sedimenting at 10-11S and 4-5S, respectively, were detected on sucrose gradients and possessed similar catalytic properties, as judged by their individual Km values toward [3H]acetylcholine (ca. 4 X 10(-4) M). The ratio between these forms varied by up to four- to fivefold, both between different areas and within particular areas at various developmental stages, but reached similar values (about 5:2) in all areas of mature brain. Acetylcholinesterase activity was ca. 35-50% low-salt-soluble and 45-65% detergent-soluble in various developmental stages and brain areas, with an increase during development of the detergent-soluble fraction of the light form. In contrast, pseudocholinesterase activity was mostly low-salt-soluble and sedimented as one component of 10-11S in all areas and developmental stages. Our findings suggest noncoordinate regulation of brain acetylcholinesterase and pseudocholinesterase, and indicate that the expression of acetylcholinesterase forms within embryonic brain areas depends both on cell type composition and on development.

Acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activity distribution pattern in early developing chick limbs

The distribution of acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activities was studied by histochemical, quantitative and electrophoretical methods during the early development of chick limbs, from stage 16 to stage 32 H.H. (Hamburger & Hamilton, 1951). By quantitative methods, true AChE activity was found, and increased about threefold during the developmental period, together with a smaller amount of BuChE which increased more rapidly in comparison with the AChE activity from stage 25 to 32 H.H. Cholinesterase activity was histochemically localized mainly in interacting tissues, such as the ectoderm (including the apical ectodermal ridge) and the underlying mesenchyme. True AChE was histochemically localized around the nuclei and on the plasma membrane of ectodermal (including AER) and mesenchymal cells, and at the plasma membrane of mesenchymal cell processes reaching the basal lamina between the ectoderm and the mesenchyme. AChE together with BuChE activity was found in the basal lamina between the ectoderm and the mesenchyme, in underlying mesenchymal cells and in deeper mesenchymal cells, especially during their transformation into unexpressed chondrocytes. During limb morphogenesis, the cellular and regional localization of the enzyme activities showed variations depending on the stage of development and on the occurrence of interactions. The possibility of morphogenetic functions of the enzyme id discussed.

高血清コリンエステラーゼ活性と過剰アイソザイムバンドを示した遺伝性変異酵素（Ｅ高松）の１家系２症例

Two members of a Japanese family (male and female) with serum pseudocholinesterase (ChE) activities elevated two to three times of the normal mean were studied for isozyme pattern by polyacrylamide gel slab and gradient gel slab electrophoresis. Beside the normal ChE bands, additional bands were observed: one between minor C3 and C4 bands, one cathodally to major C5 and one (or two) cathodally to C6 band. All the bands disappeared upon treatments with antibodies to normal ChE and also with ethopropazine. The serum ChE had normal dibucaine and fluoride numbers. In view of the fact that the properties of ChE isozyme in the present cases do not correspond to any of the described one, the variant ChE was named E. Takamatsu after its place of origin.

Ecogenetic studies on the function of pseudocholinesterase in serum of Antarctic species (Lobodon carcinophagus, Leptonychotes weddelli, Arctocephalus tropicalis and Aptenodytes fosteri)

Pseudocholinesterase activity (EC 3.1.1.8, PCHE) is present in serum of antarctic species Lobodon carcinophagus, Leptonychotes weddelli, Arctocephalus tropicalis and Aptenodytes fosteri. Compared to humans, enzyme activities were low in these species, activities were more comparable to those of the other carnivora. Dibucaine hydrochloride in concentrations of 0.01 mmol/l inhibited PCHE activity to 100% whereas sodiumfluoride inhibited PCHE in only one crabeater seal by 9%. Under standard conditions fluoride (0.05 mmol/l) activated the enzyme of all investigated species by 27.2% (range: 2.7–82.4%). Average activation was 13% in male seals and 58% in female seals (t=4.06, P=0.02). It is suggested that activation of pseudocholinesterase by fluoride is necessary for antarctic species to warrant neurochemical function controlled by acetylcholinesterase (EC 3.1.1.7).

Inhibitory effect of eseroline, an opiate like drug, on the rat nociceptive thalamic neurons activated by peripheral noxious stimuli

Eseroline is a new agent, derived from physostigmine but lacking in pseudocholinesterase activity, that possesses opioid properties in vivo and in vitro in cats and rodents. The electrophysiological effect of this drug has been investigated. Our findings show that Eseroline (5 mg/kg i.p.), suppresses the nociceptive responses evoked by noxious (mechanical and thermal) stimuli, without affecting the spontaneous firing of neurons in the thalamus of anesthetized rat. This effect starts about 5 min after the administration and lasts on average of about 60 min. Naloxone (1 mg/kg i.p.), injected 10 min before Eseroline, antagonized the antinociceptive action of this drug.

Relationship between serum lipids, lipoproteins and pseudocholinesterase during organophosphate poisoning in rabbits

1. 1. The activities of serum pseudocholinesterase, lecitin: cholesterol acyltransferase (LCAT) and γ-glutamyltransferase in rabbits were investigated before and after dichlorvos administration in vivo. The effects of this organophosphate on some serum lipids and lipoprotein fractions were also determined. 2. 2. LCAT activity remained almost unaffected after organophosphate administration. However, serum γ-glutamyltransferase and pseudocholinesterase activities markedly decreased. 3. 3. Dichlorvos markedly lowered both serum low density lipoprotein (LDL) and cholesterol contents, whereas high density lipoprotein (HDL) concentration increased and very low density lipoprotein (VLDL) remained unaffected. Triglycerides as well as esterified fatty acids increased significantly but the statistical changes in free fatty acid concentrations were not significant, because individual variations in fatty acid concentrations were high.

Rate assay for determination of serum pseudo-cholinesterase activity.

A simple and reproducible method for the determination of serum pseudo-cholinesterase activity was developed by making use of a stable substrate, p-hydroxybenzoylcholine, with p-hydroxybenzoate hydroxylase as a linked enzyme. The method is based on spectrophotometric measurement of the decrease of NADPH. p-Hydroxybenzoate released from p-hydroxybenzoylcholine is hydroxylated by the action of p-hydroxybenzoate hydroxylase in the presence of NADPH and O2 to produce 3,4-dihydroxybenzoate and NADP+. This method is superior to the conventional methods in that this substrate is extremely stable up to pH 9.0, which is close to the optimum pH for the assay (pH 8.0). Serum interference was resolved by the use of p-hydroxybenzoate hydroxylase as a linked enzyme. The Km value of pseudocholinesterase for p-hydroxybenzoylcholine is 1 X 10(-5) M. The results of our method and Garry's method (Clin. Chem. 11, 91-96, 1965) correlated well (r = 0.962). The within-run and between-run C.V. values were 2.1 and 2.7, respectively.

Weight, Pseudocholinesterase Activity, and Succinylcholine Requirement

Weight, Pseudocholinesterase Activity, and Succinylcholine Requirement

Plasma pseudocholinesterase: A potential marker for early detection of obesity

Plasma pseudocholinesterase activity, body weight and food intake showed significantly higher values in obese (ob/ob) mice than their lean littermates starting at the age of 35 days. The enzyme activity also showed a good positive correlation with age, body weight and food intake in all the mice from this age. Analysis of the data also indicated that between 35 and 58 days of age, pseudocholinesterase activity appeared to be more sensitive than body weight measurements in predicting obesity. Diabetic (db/db) mice on restricted diet, showed no significant difference in plasma pseudocholinesterase activity between the pre and post restricted blood samples. In contrast, diabetic mice on a non-restricted diet showed a significant increase in enzyme activity during the same interval of time. This suggests a relationship between hyperphagia, pseudocholinesterase and obesity.

Pseudocholinesterase Activity and Its Origin in Human Oral Fluid

Pseudocholinesterase (PCE) activity in oral fluid of 31 male and 24 female subjects was determined using butyrylthiocholine iodide as substrate. Males had approximately twice as much salivary PCE activity as did females [4.8 +/- 2.4 (S.D.) U/1 and 2.2 +/- 1.5 (S.D.) U/1, respectively]. The activity was not much affected by salivary flow rate, although in men it was a little higher in stimulated than in unstimulated saliva. Salivary PCE activity showed diurnal variation. Accordingly, activities were about three times greater at four a.m. than at four p.m. Parotid PCE activity correlated with that of whole saliva in both men and women. PCE activity in crevicular fluid (four subjects) was 120 +/- 48 (S.D.) U/1. An elevation of PCE activity in oral fluid was found after experimental induction of gingival inflammation. However, the mean PCE activity of patients with clinical gingivitis was not significantly higher than that of healthy subjects, although some exceptionally high values were found. Sonicated samples of plaque did not contain any PCE activity. No correlation existed between PCE activities in saliva and serum.

Pseudocholinesterase Staining in the Primary Visual Pathway of the Macaque Monkey.

Cholinesterases in brain tissue are divided into two main classes: ‘true’ cholinesterases (acetylcholinesterase, AChE, EC 3.1.1.7), which preferentially hydrolyse the neurotransmitter acetylcholine; and ‘pseudocholinesterases’ (for example, butyrylcholinesterase, BuChE, EC 3.1.1.8), which preferentially hydrolyse higher choline esters1. AChE is found at peripheral and central cholinergic synapses, is known to be the degradative enzyme of the cholinergic mechanism and may also have other functions in the central nervous system1–3. In contrast to AChE, the pseudocholinesterases have been assigned no certain function in neural transmission and initially were thought to occur mainly in neuroglia, Schwann cells and vascular endothelia1,4. Pseudocholinesterase activity has since been found in neurones and neuropil in several brain regions1,4,5, however, and in the superior cervical ganglion, BuChE has been localized to postsynaptic membranes6 and shown to exist in stable molecular forms corresponding to each of the known molecular forms of true cholinesterase7. These observations have led to the alternative interpretations that the pseudocholinesterases are either metabolic precursors of AChE8 or that they have functions closely related to those of AChE5,7 while being independent of true cholinesterases. We have directly compared the distributions of BuChE and AChE in the central visual pathway of the primate, a neural system in which anatomical and functional compartmentalization is well known9. We demonstrate here that the histochemical localization of Pseudocholinesterase rivals that of AChE in terms of specificity, and that BuChE is independent of AChE both in its normal distribution in the lateral geniculate body and striate cortex and in the response it shows to eye enucleation. We conclude that BuChE or its endogenous substrate may be a neuroactive substance in the primate brain.

Pseudocholinesterase activity in some human body fluids

1. 1. Pseudocholinesterase activity of sweat, lacrimal fluid, urine, parotid saliva, whole saliva, whole blood and plasma was estimated using butyrylthiocholine iodide and propionylthiocholine iodide as substrates. 2. 2. There was similarity in activity between erythrocytes and plasma, but considerable differences between whole blood and other body fluids. The level of enzyme activity was approximately the same in sweat, lacrimal fluid, urine, parotid fluid and whole saliva, but it was only about 1 1500 of that of plasma. 3. 3. The enzyme activity in either whole blood or plasma is a good measure of organophosphate exposure but in other fluids activity can hardly give more than an approximate indication of acute poisoning.

The relationships between human serum pseudocholinesterase, lipoproteins, and apolipoproteins (APOHDL)

During recent years there has been an increasing number of studies concerning metabolizing enzymes during lipoprotein catabolism. It is well documented that lecithin-cholesterol acyltransferase (LCAT, ED 2.3.1.43) and lipoprotein lipase (EC 3.1.1.34) take part with these reactions (1). In addition to these enzymes there has been evidence that pseudocholinesterase (EC 3.1.1.8.) is also associated with lipid metabolism (2). A relationship between serum pseudocholinesterase and low density lipoprotein (LDL) has been shown on the basis of ultrasonication studies (3) and after artifical induction of hyperlipidemia in vitro and in vivo (4). Because pseudocholinesterase activity has been previously measured only in whole serum and in DLD, our purpose has been to find out if there is any activity in other lipoprotein fractions. In addition to whole enzyme activity we investigated the distribution of pseudocholinesterase (PCE) isoenzymes in different fractions. As previously reported, LCAT and lipoprotein lipase need as cofactor, a specific apolipoprotein (5). We also studied a possible connection between HDL (high density lipoprotein) apolipoproteins (apoA-I, A-II, E, and total apoC) and PCE activity.