Erythrocyte Membrane Acetylcholinesterase Research Articles

Erythrocyte membrane fluidity in mild cognitive impairment and Alzheimer's disease patients.

Alzheimer's disease (AD) is the most common cause of dementia accounting for 60-70% of all demented cases and one of the leading sources of morbidity and mortality in the aging population. Most of the recent literature regards the relationship between plasma oxidative stress and AD, showing that markers of lipid peroxidation are significantly higher in AD and Mild Cognitive Impairment (MCI) patients with respect to control subjects. The increased generation of reactive oxygen species that occurs in AD may be also responsible for oxidative injury to erythrocyte membranes. Since erythrocyte membrane serves as a variable barrier to oxygen transport, changes in its stability can induce cellular hypoxia and the consequence brain tissue oxygenation. In this study, plasma oxygen radical absorbance capacity (ORAC) and erythrocyte membrane fluidity have been evaluated in control, MCI and AD patients. Moreover erythrocyte membrane acetylcholinesterase (AchE) activity has been measured in control and AD patients. Plasma ORAC significantly decreased in MCI and AD subjects with respect to the controls, while a decrease in erythrocyte membrane fluidity has been observed only in MCI patients. No significant differences were detected in erythrocyte AchE activity between control subjects and AD patients.

Human Erythrocyte Acetylcholinesterase in Health and Disease.

The biochemical properties of erythrocyte or human red blood cell (RBC) membrane acetylcholinesterase (AChE) and its applications on laboratory class and on research are reviewed. Evidence of the biochemical and the pathophysiological properties like the association between the RBC AChE enzyme activity and the clinical and biophysical parameters implicated in several diseases are overviewed, and the achievement of RBC AChE as a biomarker and as a prognostic factor are presented. Beyond its function as an enzyme, a special focus is highlighted in this review for a new function of the RBC AChE, namely a component of the signal transduction pathway of nitric oxide.

Physiological role of erythrocyte nitric oxide.

Nitric oxide (NO) produced by endothelial cells interacts with erythrocyte through band 3 protein, being scavenged by haemoglobin. A signal transduction mechanism involving protein Gi and protein band 3 stimulates erythrocyte NO efflux when acetylcholine (ACh) binds to erythrocyte membrane acetylcholinesterase. Binding of normal plasma fibrinogen (Fib) levels, to erythrocyte membrane CD47 decreases the NO efflux. When high Fib concentration and ACh were present the efflux of NO from erythrocytes was normalized. The increased NO efflux from erythrocytes in presence of high Fib concentration and band 3 phosphorylation is reinforced in the presence of 4N1K an agonist peptide of CD47. When both Fib and 4N1K are present the NO efflux from erythrocytes is higher or not affected according lower or high levels of cAMP. Erythrocyte NO efflux in patients with systemic lupus erythematous and rheumatoid attrite was significantly negative associated with carotid intima-media thickness. In patients with amyotrophic lateral sclerosis erythrocyte NO content is preserved and an inverse association between respiratory function and NO efflux from the erythrocyte was verified. Sepsis patients before dead at 24 h showed higher efflux of NO from erythrocytes that worsening the blood sub lingual microcirculation observed by high unequal blood flow and high microvascular flow index. The in vivo animal models either of inflammation or of hypertension evidenced that the NO efflux from erythrocyte decrease as a compensatory mechanism. All studies conducted since 2000 where we demonstrated the existence NO inside the erythrocyte by fluorescence microscopy, and after their signaling pathway needs more development translational research for news therapeutics and further application in not invasive therapy to vascular inflammatory diseases.

Report of the meeting on Aspartame with National Experts

Report of the meeting on Aspartame with National Experts

The effect of the mode of delivery on the maternal–neonatal erythrocyte membrane acetylcholinesterase activity

Free radical production and high catecholamine levels are implicated with the modulation of acetylcholinesterase (AChE) activity. Objective To investigate the effect of the mode of delivery on maternal–neonatal erythrocyte membrane AChE activity. Subjects and methods Some women with normal pregnancy ( N = 30) were divided into two groups: group A ( N = 16) with normal labour and vaginal delivery and group B ( N = 14) with scheduled Cesarean section, twenty non-pregnant women were the controls. Blood was obtained from controls and from mothers pre- vs post-delivery as well as from the umbilical cord (CB). Total antioxidant status (TAS), membrane AChE activities and catecholamine blood levels were measured with a commercial kit, spectrophotometrically and HPLC methods, respectively. Results TAS and catecholamine levels as well as membrane AChE activities were similar in the two groups of mothers pre-delivery and in controls. TAS levels were reduced whereas AChE activities and catecholamine levels were increased post-delivery in mothers of group A and unaltered in group B at the same times of study. AChE activity was similarly lower in the CB of neonates than those of their mothers pre-delivery. Conclusions During a normal delivery process, the low TAS, the increased levels of catecholamines and the increased AChE activity, post-delivery, may be due to the increased stress due to the participation of uterus and skeletal muscles as during endurance exercise. The low AChE activity in newborns may be related to perinatal immaturity.

Abnormal degradation of erythrocyte membrane proteins in Down's syndrome

HereditasVolume 106, Issue 1 p. 151-153 Open Access Abnormal degradation of erythrocyte membrane proteins in Down's syndrome M. GACZYNSKA, M. GACZYNSKA Chair of Biophysics, University of Lódź, 90–237 Lódź Department of BiochemistrySearch for more papers by this authorJ. ROSIN, J. ROSIN Institute of Occupational Medici, Department of Physiology, Institute of Fundamental SciencesSearch for more papers by this authorG. BARTOSZ, G. BARTOSZ Chair of Biophysics, University of Lódź, 90–237 Lódź Department of BiochemistrySearch for more papers by this authorJ. KeDZIORA, Corresponding Author J. KeDZIORA WAM and 4th Clinical Hospital*Department of Physiology Institute of Fundamental Sciences “WAM” Medical Academy Plac 9 Maja No. 1 90–647 Lódź. PolandSearch for more papers by this authorJ. JESKE, J. JESKE Medical Academy of LódźSearch for more papers by this author M. GACZYNSKA, M. GACZYNSKA Chair of Biophysics, University of Lódź, 90–237 Lódź Department of BiochemistrySearch for more papers by this authorJ. ROSIN, J. ROSIN Institute of Occupational Medici, Department of Physiology, Institute of Fundamental SciencesSearch for more papers by this authorG. BARTOSZ, G. BARTOSZ Chair of Biophysics, University of Lódź, 90–237 Lódź Department of BiochemistrySearch for more papers by this authorJ. KeDZIORA, Corresponding Author J. KeDZIORA WAM and 4th Clinical Hospital*Department of Physiology Institute of Fundamental Sciences “WAM” Medical Academy Plac 9 Maja No. 1 90–647 Lódź. PolandSearch for more papers by this authorJ. JESKE, J. JESKE Medical Academy of LódźSearch for more papers by this author First published: March 1987 https://doi.org/10.1111/j.1601-5223.1987.tb00248.xAboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Literature cited Asano, K., Osawa, Y., Yanagisawa, N., Takahashi, Y. and Oshima, M. 1985. Erythrocyte membrane abnormalities in patients with amyotrophic chorea with acanthocythosis. Part 2. Abnormal degradation of membrane proteins. J. Neurol. Sci. 68: 161– 173. Bartosz, G. and Kȩdziora, J. 1982. Aging of the erythrocyte. XX. Decreased red cell life span in Down's syndrome. Cell Biol. Inl. Rep. 6: 1119– 1122. Bartosz, G., Soszynski, M. and Kȩdziora J. 1982. Aging of the erythrocyte. VI. Accelerated red cell membranes aging in Down's syndrome Cell Biol. Int. Rep. 6: 73– 77. Gaczyńska, M., Bartosz, G., Rosin, J. and Soszyński, M. 1985. Proteolytic self-digestion of bovine erythrocyte membranes. Int. J. Biochem. 17: 1237– 1245. Kay, M.M.B., Goodman, S., Sörensen, K., Whitfield, C., Wong, P., Zaki, L. and Rudloff, V. 1983. Senescent cell antigen is immunologically related to band 3. Proc. Natl. Acad. Sci. U.S.A 80: 1631– 1635. Kȩdziora, J., Hly7nacute;czak, A. J., Jeske. J. and Kański, M. 1972. Physicochemical properties and metabolism of erythro-cytes in children with Down's syndrome. Pol. Endocrinol. 23: 63– 70. Kȩdziora, J., Bartosz, G., Koter, M. and Leyko, W. 1982a. Erythrocyte membrane acetylcholinesterase in Down's syndrome. IRCS Med. Sci. 10: 785. Kȩdziora, J., Koter, M. and Bartosz, G. 1982b. Influence of acrocentric chromosome G-21 on the structural changes of erythrocyte membranes. Stud. Biophys. 90: 119– 120. Koter, M., Kȩdziora, J., Bartosz, G. and Leyko, W. 1982. Down's syndrome: permeability of the erythrocyte membrane for spin-labeled non-electrolytes Experientia 38: 1447. Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227: 680– 685. Melloni. E., Salamino, F., Sparatore, B., Michetti, M. and Pontremoli, S., 1982. Cooperation between soluble and membrane bound proteinases in the degradation of β-hemoglobin chains in intact human erythrocytes. Archs. Biochem. Biophys. 216: 495– 502. Volume106, Issue1March 1987Pages 151-153 ReferencesRelatedInformation

The in vivo and in vitro effects of L-carnitine supplementation on the erythrocyte membrane acetylcholinesterase, Na+, K+-ATPase and Mg2+-ATPase activities in basketball players

We investigated whether the activities of erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase are modulated in basketball players pre- vs. post-forced training with or without L-carnitine (L-C) supplementation. Blood was obtained from 10 male players pre-game (group A) and post-game (group B) and after 1 month L-C supplementation (2 g/24 h orally) pre-training (group C) and post-training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured with commercial kits, catecholamines with HPLC and the enzyme activities spectrophotometrically. Lactate, pyruvate, AChE, Na+, K+-ATPase and catecholamines were increased (p<0.001) and TAS was decreased (p<0.001) in group B. In contrast, TAS remained unaltered and the all enzyme activities were reduced (p<0.001) in group D at the same time of study. Mg2+-ATPase activity remained unchanged. In vitro incubation of the modulated AChE and Na+, K+-ATPase with L-C (25 microM) from group B and group D resulted in a non-significant reduction of the enzymes in group B and complete restoration of their activities in group D. The increase of AChE and Na+, K+-ATPase activities may be due to the elevation of catecholamines in group B. Carnitine utilization by the muscles during training may result in a reduction of the enzyme activities (group D). The latter is supported by the recovery of the enzyme activities after incubation of the membranes from group D with L-C.

The Effect of Basketball Training on the Players' Erythrocyte Membrane Acetylcholinesterase, (Na+,K+)-ATPase and Mg2+-ATPase Activities

The aim of this study was to investigate whether the activities of erythrocyte membrane acetylcholinesterase (AChE), (Na (+),K (+))-ATPase and Mg (2+)-ATPase are modulated by a basketball training. Blood was obtained from 10 basketball players pre- and postexercise. Total antioxidant status (TAS), lactate and pyruvate concentrations were determined with kits, while the enzyme activities were determined spectrophotometrically. Post-training blood lactate and pyruvate concentrations as well as AChE (2.90 +/- 0.05 vs. 3.98 +/- 0.09 Delta OD/min . mg protein, p < 0.01) and Na (+),K (+)-ATPase (0.58 +/- 0.04 vs. 1.27 +/- 0.12 micromol Pi/h . mg protein, p < 0.001) activities were remarkably increased, whereas TAS was significantly decreased. Mg (2+)-ATPase activity remained unaltered at the end of the training. In conclusion, the stimulation of AChE and Na (+),K (+)-ATPase by the training may be due to the rise of blood catecholamine oxidation contributing to TAS decrease and/or the increase of serotonin levels. This stress condition may modulate cholinergic and catecholaminergic/serotoninergic functions in players.

L-Cysteine supplementation prevents exercise-induced alterations in human erythrocyte membrane acetylcholinesterase and Na+,K+-ATPase activities

L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase induced by free radicals in basketball players during training. Blood was obtained from 10 basketball male players before (group A) and after a game (group B) and after 1 week of L-Cys (0.5 g/24 h orally) supplementation before (group C) and after training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured using commercial kits and the enzyme activities were determined spectrophotometrically. Both lactate and pyruvate levels remarkably increased after exercise. In contrast, TAS levels significantly decreased in group B, increased in group C and then declined (group D), reaching those of group A. AChE activity was statistically increased post-exercise (3.98+/-0.04 Delta OD/min x mg protein) compared with pre-training (2.90+/-0.05 Delta OD/min x mg protein, p<0.01). Na(+),K(+)-ATPase activity was also higher post-exercise (1.27+/-0.05 micromol Pi/h x mg protein) than that pre-exercise (0.58+/-0.04 micromol Pi/h x mg protein, p<0.001). When the players were supplemented with L-Cys, both AChE and Na(+),K(+)-ATPase activities remained unaltered post-exercise. Mg(2+)-ATPase activities were unchanged in all groups studied. L-Cys supplementation may protect the enzyme activities studied against stimulation induced by free radical production during training in athletes by ameliorating their total antioxidant capacity.

An in vivo and in vitro study of erythrocyte membrane acetylcholinesterase, (Na +, K +)-ATPase and Mg 2+-ATPase activities in basketball players on α-tocopherol supplementation. The role of l-carnitine

Vitamin E (alpha-tocopherol, alpha-Te) and carnitine reduce lipid peroxidation. THE AIM WAS TO: To investigate the erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities in basketball players with or without alpha-Te supplementation, before and after training. In vitro, we aimed to find out any additional effect of L-carnitine (L-C) on the modulated enzyme activities. Blood was obtained from 10 players before (group A), after exercise (group B) and after 1 month on alpha-Te (200 mg/24 h orally) supplementation before (group C) and after the game (group D). Lactate, pyruvate, muscle enzyme activities and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and alpha-Te were determined with HPLC methods and membrane enzyme activities spectrophotometrically. Lactate, pyruvate, muscle enzymes and catecholamine levels were increased (P<0.001) in all groups after training. Alpha-Te levels and Mg2+-ATPase activity remained unaltered before and after exercise. TAS was decreased in the groups after the game. AChE activity was increased in group B (P<0.01) and decreased in group D (P<0.01). After the exercise, Na+, K+-ATPase activity was increased in group B and remained unaltered in group D. In vitro incubation of membranes from group D with L-C resulted in a partially restoration of the membrane AChE activity, whereas Na+, K+-ATPase and Mg2+-ATPase activities were found unchanged. Alpha-Te supplementation in basketball players results in an increase of TAS and AChE activity, whereas the other enzyme activities were found unchanged. L-C addition may restore AChE activity, which was modulated by training in players on alpha-Te.

Erythrocyte membrane acetylcholinesterase activity in subjects with MTHFR 677C→T genotype

Increased homocysteine (Hcy) blood levels are correlated with vascular and neurological problems. The aim of the present study was to investigate erythrocyte membrane acetylcholinesterase (AChE) activity in subjects with the MTHFR C677T genotype in relation to Hcy. Blood was obtained from 22 individuals with the MTHFR C677T genotype before and after folic acid supplementation and once from controls (n = 30). Plasma folate, vitamin B(12) and total antioxidant status (TAS) were measured with commercial kits, Hcy by a HPLC method and membrane enzyme activity spectrophotometrically. In MTHFR C677T carriers, AChE activity was significantly higher (4.20 +/- 0.12 x mg protein) and decreased to normal levels (3.14 +/- 0.10 x mg protein; p < 0.001) after therapy. TAS differed slightly before and after treatment. Hcy levels were significantly higher before (22.4 +/- 2.8 microM) compared to after (12.1 +/- 2.0 microM; p < 0.001) therapy and compared to controls (10.5 +/- 2.5 micromol/L; p < 0.001). In an in vitro study, incubation of Hcy-activated membrane AChE from controls with phenylalanine resulted in restoration of activity, but failed to reverse the stimulated enzyme from hyperhomocysteinaemic MTHFR C677T subjects before therapy. Alanine incubation protected the enzyme from Hcy activation in controls. Increased membrane AChE activity may be due to high Hcy levels. In vitro, phenylalanine reversed the Hcy activation of the membrane enzyme from controls and alanine protected it from Hcy action.

Erythrocyte membrane acetylcholinesterase, Na+, K+‐ATPase and Mg2+‐ATPase activities in patients with classical galactosaemia

Classical galactosaemia is commonly presented by high blood galactose (Gal) and galactose-1-phosphate (Gal-1-P) levels followed by mental retardation, seizures, etc. dependent on the mutation of the patients. To evaluate Gal and Gal-1-P in the blood of patients and to correlate their levels with their erythrocyte membrane acetylcholinesterase (AChE), Na+,K+-ATPase and Mg2+-ATPase activities. Blood was obtained from nine patients on poor diet (group B) followed by a 30-d strict diet (group A) and controls (group C) in order to evaluate Gal and Gal-1-P in Guthrie cards and to correlate their concentrations with the above enzyme activities, which were measured spectrophotometrically. With the patients on a "loose" diet, AChE, Na+,K+-ATPase and Mg2+-ATPase activities were found to be decreased, as compared with those on strict diet and controls. Significantly (p<0.01) inverse correlation coefficients of the enzyme activities were found with Gal-1-P levels. (a) AChE, Na+,K+-ATPase and Mg2+-ATPase activities were determined to be decreased in poorly controlled patients with classical galactosaemia. (b) The enzyme activities were inversely correlated with the Gal-1-P blood levels. (c) Since Na+,K+-ATPase in the erythrocyte membranes is the isomer of Na+,K+-ATPase distributed in many tissues and in the brain, evaluation of the enzyme activity in the erythrocytes could be a useful peripheral marker of Gal-1-P toxicity.

The effect of aspartame metabolites on human erythrocyte membrane acetylcholinesterase activity

Studies have implicated aspartame (ASP) with neurological problems. The aim of this study was to evaluate acetylcholinesterase (AChE) activity in human erythrocyte membranes after incubation with the sum of ASP metabolites, phenylalanine (Phe), methanol (met) and aspartic acid (aspt), or with each one separately. Erythrocyte membranes were obtained from 12 healthy individuals and were incubated with ASP hydrolysis products for 1 h at 37 °C. AChE was measured spectrophotometrically. Incubation of membranes with ASP metabolites corresponding with 34 mg/kg, 150 mg/kg or 200 mg/kg of ASP consumption resulted in an enzyme activity reduction by −33%, −41%, and −57%, respectively. Met concentrations 0.14 mM, 0.60 mM, and 0.80 mM decreased the enzyme activity by −20%, −32% or −40%, respectively. Aspt concentrations 2.80 mM, 7.60 mM or 10.0 mM inhibited membrane AChE acitivity by −20%, −35%, and −47%, respectively. Phe concentrations 0.14 mM, 0.35 mM or 0.50 mM reduced the enzyme activity by −11%, −33%, and −35%, respectively. Aspt or Phe concentrations 0.82 mM or 0.07 mM, respectively, did not alter the membrane AChE activity. It is concluded that low concentrations of ASP metabolites had no effect on the membrane enzyme activity, whereas high or toxic concentrations partially or remarkably decreased the membrane AChE activity, respectively. Additionally, neurological symptoms, including learning and memory processes, may be related to the high or toxic concentrations of the sweetener metabolites.

Antimalarials Inhibit Human Erythrocyte Membrane Acetylcholinesterase

The current study examined the ability of antimalarials chloroquine (CQ), primaquine (PQ), and quinine (Q) to inhibit human erythrocyte membrane acetylcholinesterase (AChE) and the mechanisms underlying their inhibitory action. CQ was found to be the most effective inhibitor of the enzyme followed by PQ and Q. The concentrations required to obtain 33% inhibition (IC33) for CQ and PQ were 22 and 38 µM, respectively, whereas that for Q was 3.2 mM. The concentrations required to obtain 67% inhibition (IC67) were about 9 and 7 times higher for CQ and PQ, whereas that for Q was only about 2.5 times higher. Hill plot analysis revealed that CQ shows de-binding above 40 µM. The two kinetic components of AChE were inhibited by the three antimalarials, and the inhibition was of mixed type. Increasing concentrations of antimalarials caused progressive decrease in the Vmax of both components. IC33 concentrations resulted in 1.6- to 6-fold increase in Km of both the components while IC67 concentration caused 2.8- to 13-fold increases in Km with maximum effect being seen with Q. The Ki values were lowest for CQ suggesting that it was the most potent inhibitor; these values were 3.3 and 60 times higher for PQ and Q. Antimalarials represent the bifunctional compounds that possess anti-inflammatory properties and also inhibit cholinesterases. The results of our studies suggest that 4-aminoquinoline–based antimalarials like CQ and hydroxychloroquine, which are both potent anti-inflammatory agents and inhibitors of cholinesterases, may have potential use as the most effective neuroprotective agents against amyloid-β-peptide (Aβ) neurotoxicity in Alzheimers disease.

The effect of polyamidoamine dendrimers on human erythrocyte membrane acetylcholinesterase activity

Polyamidoamine (PAMAM) dendrimers impact on activity of acetylcholinesterase was studied. It has been shown that dendrimers induce a biphasic effect: depending on their concentrations they increase or decrease enzyme activity. It may be due to two types of interactions: direct—between dendrimers and the enzyme; indirect—via a modification of the physical state of membrane phospholipids affecting the acetylcholinesterase.

Insulin-like effect of (-)epicatechin on erythrocyte membrane acetylcholinesterase activity in type 2 diabetes mellitus.

1. Changes in the activity of acetylcholinesterase (AChE) have been reported in diabetes mellitus that have been linked to certain brain defects. The erythrocyte membrane AChE is reported to be similar to AChE present in the brain. 2. Epicatechin, a member of a group of polyphenolic compounds collectively known as "catechins" that are present in tea and belong to the flavonoid family, has been reported to possess insulin-like activity. 3. In the present study, the in vitro effect of (-)epicatechin and/or insulin was tested on erythrocyte membrane AChE in normal and type 2 diabetic patients. The aim of the study was to test the efficacy of (-)epicatechin to mimic insulin in its effect on erythrocyte membrane AChE. 4. Acetylcholinesterase activity was significantly lower in type 2 diabetic patients than in normal controls and in vitro insulin treatment restored this activity to normal levels. Epicatechin (1 mmol/L) also caused an elevation in AChE activity in diabetic erythrocytes, an effect that was similar to the effect of insulin. 5. Epicatechin has a pronounced insulin-like effect on erythrocyte membrane-bound AChE in type 2 diabetic patients; however, the mechanism of action of epicatechin remains speculative.

Insulin or sulfonylurea treatments of the diabetics differentially affect erythrocyte membrane and serum enzymes and extent of protein glycosylation

Erythrocyte membrane protein glycosylation increase by 3.4 fold in diabetes. Insulin or sulfonylurea treatment did not reduce the extent of glycosylation. The serum protein glycosylation was comparable in all the groups including control. Erythrocyte membrane Na(+),K(+)-ATPase activity decreased in the diabetics; only insulin treatment partly restored the activity. Erythrocyte membrane acetylcholinesterase activity decreased only in the sulfonylurea treated group. Serum butyrylcholinesterase activity was relatively low in the diabetic and insulin treated diabetic groups. The Km and Vmax of the two components of Na(+),K(+)-ATPase from erythrocyte membranes were differently affected in the diabetic and the two treatment groups. The Vmax of acetylcholinesterase decreased only in the sulfonylurea treated group. Diabetic states resulted in decreased Vmax of components I and II of serum butyrylcholinesterase. In insulin-treated diabetics, component II was absent. Sulfonylurea group resembled diabetics.In vitro incubation with insulin differentially affected the Na(+),K(+)-ATPase and serum butyrylcholinesterase activities.

Effect of combined treatment with perindoprilat and low-power red light laser irradiation on human erythrocyte membrane fluidity, membrane potential and acetylcholinesterase activity

Erythrocyte membrane fluidity, membrane potential and acetylcholinesterase activity were estimated after in vitro combined treatment of human erythrocytes with perindoprilat and low-power red light irradiation. Membrane fluidity was determined using fluorescent labels spectroscopy; membrane potential was evaluated by means of potential-sensitive fluorescent dyes; and acetylcholinesterase activity was estimated using the Ellman method. Both perindoprilat and laser irradiation, when used separately, increase microviscosity in the polar region and hyperpolarize the membranes in comparison with control erythrocytes. The combined action of these agents does not cause any further change in these parameters. Perindoprilat has an additional inhibitory effect on the activity of acetylcholinesterase, whereas laser irradiation causes an increase in the activity of the enzyme. Their combined action restores the initial activity of the enzyme independently of the sequence of treatment with both agents.

Effect of peroxynitrite on erythrocytes

The action of peroxynitrite on human erythrocytes and erythrocyte membranes was studied. Peroxynitrite (0.1–2 mM) induced a transient decrease of intracellular reduced glutathione, oxidized membrane protein -SH groups, initiated membrane lipid peroxidation and inactivated erythrocyte membrane acetylcholinesterase and ATPase activities. Membranes exposed to peroxynitrite showed aggregation and nitration of proteins and changes in protein organization detectable with a maleimide spin label.

Influence of cetiedil on erythrocyte membrane microviscosity and acetylcholinesterase activity

Since one of the cellular targets of cetiedil, a vaso-erythroactive drug, is likely to be the erythrocyte membrane, we have studied the influence of this drug on erythrocyte membrane microviscosity and acetylcholinesterase activity. No effect was evidenced on microviscosity, as measured by fluorescence polarization of light emitted by DPH or TMA-DPH labelling of the lipid bilayer. Cetiedil, however, did lower acetylcholinesterase activity, but it did not directly inhibit this enzyme activity. It can therefore be considered as an amphiphilic drug that perturbs membrane properties without affecting the physical state of the erythrocyte membrane.