Acetylcholinesterase Activity In Tissues Research Articles

Flaxseeds (L. Usitatissimum) attenuates blood pressure, acetylcholinesterase activity and oxidative stress in ouabain-induced hypertension in normal Wistar rats

PurposeThe purpose of this study is to evaluate the effects of flaxseed (L. usitatissimum [Linn]) on blood pressure, redox status markers and acetylcholinesterase enzyme activity in ouabain-induced hypertension in normal Wistar rats.Design/methodology/approachMale Wistar rats weighing 250 ± 7 g (n = 24) fed with an experimental diet containing 20 per cent casein were divided into three groups (n = 8) and received a daily subcutaneous injection of either 0.9 per cent saline solution (T group) or 10 µg/kg/day of ouabain diluted in saline solution-treated Oub-Lu or not with 1 per cent of flaxseed (L. usitatissimum) mixed in the diet for 21 days.FindingsThe results showed that treatment with flaxseed had a significant effect (p < 0.05) in decreasing systolic, diastolic blood pressure, mean arterial pressure and the heart rate in hypertensive rats. Total and non-HDL cholesterol levels were reduced by –26 and –35 per cent; p = 0.04, respectively. Concentrations of thiobarbituric acid-reactive substances were significantly decreased by –85 and –42 per cent (p = 0.001 and p = 0.04), respectively in the plasma and heart. Nitric oxide levels were increased in the aorta (+ 63 per cent; p = 0.001). Moreover, in the heart and aorta, a significant increase was noted in the thiol contents (+81 and +69 per cent; p = 0.001, respectively), glutathione peroxidase (+50 per cent; p = 0.03 and p = 0.01, respectively) and acetylcholinesterase activities (75 and +19 per cent, respectively; p = 0.001 and p = 0.04).Originality/valueThese results suggest hypotensive, cardiomoderating and antioxidant effects of flaxseed in ouabain-induced hypertension in the rat. In addition, it promotes a significant increase of the acetylcholinesterase activity in tissues.

Alterations in Plasma and Tissue Acetylcholinesterase Activity Following Repeated Oral Exposure of Chlorpyrifos Alone and in Conjunction with Fluoride in Wistar Rats

Concurrent exposures of more than one environmental contaminants are commonly encountered by human beings and animals. This study investigated the effect of chlorpyrifos alone and in conjunction with fluoride on plasma and tissue acetylcholinesterase (AChE) activity in wistar rats. Fluoride at 1 or 10 ppm in drinking water produced significant (P < 0.05) inhibition of AChE activity in a dose dependant manner and inhibition was maximum in brain (26.39 %) and least in heart (10.23 %). Similarly repeated oral administration of chlorpyrifos at 1 or 10 mg/kg produced a significant dose dependant inhibition of AChE activity (P < 0.05) which was observed maximum in brain (28.93 %) and least in heart (12.86 %). Co-exposure of chlorpyrifos and fluoride at higher doses produces more pronounced inhibition as compared to chlorpyrifos or fluoride exposed groups. Co-exposure produces maximum inhibition in erythrocyte (37.54 %) and least in plasma (18.26 %) of exposed animals as compared to control group. Observations from the present study suggested that co-exposure of fluoride and chlorpyrifos produces more pronounced inhibition of AChE than the individual exposure of either toxicant. Therefore the applications of chlorpyrifos as a pesticide should be reduced in areas where fluoride level in soil or ground water is high to avoid AChE inhibition.

Seasonal exposure of fish to neurotoxic pesticides in an intensive agricultural catchment, Uma‐oya, Sri Lanka: Linking contamination and acetylcholinesterase inhibition

The annual cultivation pattern in the Uma-oya catchment in Sri Lanka is characterized by Yala and Maha rainfall periods and associated cropping. Two cultivation seasons were compared for pesticide residues: base flow, field drainage, and the runoff and supplementary sediment data for three sites in the catchment. Organophosphate and N-methyl carbamate pesticide analysis confirmed a higher concentration in the Yala season with low-flow conditions. Acetylcholinesterase (AChE) activity was measured by standard spectrometry in the brain, muscle, and eye tissues of three freshwater cyprinid fishes, Garra ceylonensis, Devario malabaricus, and Rasbora daniconius from three study sites during months overlapping two seasons in 2010 (December) and 2011 (July). Baseline AChE data were measured from fish samples from a forested reserve in the Knuckles. A 73% inhibition in muscle AChE activity in G. ceylonensis was associated with intense pesticide exposure months in the Yala season. The AChE inhibition more than 70% in G. ceylonensis eyes in both Yala (76%) and Maha (72.5%) seasons indicates particular sensitivity of eye tissue to inhibitors. The less dramatic AChE inhibition in the eye tissues in D. malabaricus and R. daniconius in both seasons indicates exemplary protective capacity of muscle AChE in fish. The highest inhibition of AChE (up to 60% in brain and up to 56% in muscle AChE activity in R. daniconius and up to 47.8% in brain and up to 64.6% in muscle AChE activity in D. malabaricus) occurred during the Yala season. Tissue AChE activity and physiological activity in fish were correlated. The results collectively indicate that AChE is a consistent biomarker for diffused contaminant exposure in agricultural catchments.

Polyethylene glycosylation prolongs the stability of recombinant human paraoxonase-1

Paraoxonase-1 (PON1) is a native enzyme that is synthesized in the liver and is capable of hydrolyzing organophosphates (OPs). It is regarded as part of a promising approach for the pretreatment and therapy of OP poisoning. Previous experiments with purified rabbit serum PON1 have established that it can protect rats against many OP exposures. In the current paper, we described a preparation of active recombinant human PON1 (rHuPON1) by engineering an Escherichia coli expression system. Recombinant HuPON1 was purified by Ni-NTA affinity chromatography followed by DEAE sepharose fast-flow chromatography. After purification, rHuPON1 was chemically modified with polyethyleneglycol (PEG)-20K. Recombinant HuPON1 exhibited a mean residence time (MRT) of 8.9h, which was threefold shorter than that of native HuPON1 in rats. However, rHuPON1 chemically modified with PEG-20K displayed an MRT of 19.5h, suggesting that PEG modification can prolong the circulatory stability of rHuPON1. PEG-rHuPON1 had a catalytic efficiency sufficient in protecting rats against OP poisoning, as measured by acetylcholinesterase activity in tissues and signs after poisoning.

Effects of exposure to oxamyl, carbofuran, dichlorvos, and lindane on acetylcholinesterase activity in the gills of the Pacific oyster Crassostrea gigas

Acetylcholinesterase (AChE) activity has been used to test the exposure of mollusk bivalves to pesticides and other pollutants. The Pacific oyster Crassostrea gigas is a species with a worldwide distribution, and it has a high commercial value. The use of this species as a bioindicator in the marine environment, and the use of measurements of AChE activity in tissues of C. gigas require prior evaluation of organisms exposed to several toxic compounds in the laboratory. In our study, the effects of pesticides on AChE activity in the gills and mantle tissues of C. gigas were analyzed by exposing animals to organophosphate (dichlorvos), carbamate (carbofuran and oxamyl), and organochlorine (lindane) pesticides. Adult Pacific oysters were exposed to several concentrations (0.1-200 microM) of dichlorvos, carbofuran, and oxamyl for 96 h, and lindane (1.0 and 2.5 microM) was applied for 12 days. In gill tissues, all pesticides analyzed caused a decrease in AChE activity when compared to the control unexposed group. The mean inhibition concentration (IC(50)) values were determined for dichlorvos, carbofuran, and oxamyl pesticides. Dichlorvos had the highest toxic effect, with an IC(50) of 1.08 microM; lesser effects were caused by oxamyl and carbofuran, with IC(50)s of 1.67 and 3.03 microM, respectively. This study reports the effects of pesticides with several chemical structures and validates measurement of AChE activity in the gill tissues of C. gigas for use in environmental evaluations or food quality tests.

Effects In Vitro of Guanidinoacetate on Adenine Nucleotide Hydrolysis and Acetylcholinesterase Activity in Tissues from Adult Rats

Guanidinoacetate methyltransferase (GAMT) deficiency is a disorder of creatine metabolism characterized by low plasma creatine concentrations in combination with elevated guanidinoacetate (GAA) concentrations. The aim of this work was to investigate the in vitro effect of guanidinoacetate in NTPDase, 5'-nucleotidase and acetylcholinesterase activities in the synaptosomes, platelets and blood of rats. The results showed that in synaptosomes the NTPDase and 5'-nucleotidase activities were inhibited significantly in the presence of GAA at concentrations of 50, 100, 150 and 200 microM (P < 0.05). However, in platelets GAA at the same concentrations caused a significant increase in the activities of these two enzymes (P < 0.05). In relation to the acetylcholinesterase activity, GAA caused a significant inhibition in the activity of this enzyme in blood at concentrations of 150 and 200 microM (P < 0.05), but did not alter the acetylcholinesterase activity in synaptosomes from the cerebral cortex. Our results suggest that alterations caused by GAA in the activities of these enzymes may contribute to the understanding of the neurological dysfunction of GAMT-deficient patients.

The effect of pesticides on carp ( Cyprinus carpio L). Acetylcholinesterase and its biochemical characterization

The activity and molecular forms of acetylcholinesterase (AChE) were characterized in tissues of the carp ( Cyprinus carpio). Tissue AChE activity was determined in response to specific inhibitors (ethopropazine, BW 284 C51) or pesticides (CuSO 4, paraquat (PQ), methidathion (MD)). The highest AChE activity was found in the serum (878 ± 100 U/liter), followed by the brain (113 ± 12 U/liter), heart (89 ± 6 U/liter), and trunk muscle (35 ± 5 U/liter). Experiments with specific choline esterase inhibitors revealed a very low amount of pseudocholinesterase in all tissues studied. The ratio of the membrane-bound to the cytoplasmic-free AChE molecular forms was increased in the order of brain, trunk muscle, and heart. In sera of fish treated with MD (2 ppm) there was an 80% inhibition of AChE lasting for 2 weeks. Treatment with CuSO 4 or PQ (both 5 ppm) led to a 50% decrease in the serum AChE activity followed by a transient increase over the control level. After 2 weeks of chronic treatment, AChE activity in fish exposed to CuSO 4 returned to the control level, whereas in fish treated with PQ an elevated level (130% when compared to the control level) of enzyme activity was found. Our present experimental data indicate that pesticides occurring in natural waters not only inhibit AChE activity in fish but may influence the resynthesis of the enzyme as well.

Nutrition and fetal brain maturation: II. Impact of maternal starvation on changing levels of acetylcholinesterase and enolase in vitro

The impact of maternal starvation during Days 17–20 of gestation was examined in 20-day fetal rat brain tissue cultured for 6 days in MEM and 10% adult rat serum. Acetylcholinesterase (AChE) activities were consistently greater in fetal brain cell cultures from starved mothers. When fetal tissues from starved mothers were continuously exposed to 72-h fasted serum, AChE activities increased from 1.03±0.14 to 1.59±0.21 μmol/h/mg protein ( P<0.001). In fetal tissues from fed mothers, lower AChE activities were increased from 0.78±0.09 to 1.04±0.07 μmol/h/mg protein ( P<0.05) when 72-h fasted serum was used to replace the fed serum during incubation. When fetal brain cell cultures from fed mothers were exposed for 6 days to graded concentrations of fed serum (2.5–15%), the activities of AChE fell reciprocally from 1.34±0.10 to 0.82±0.12 μmol/h/mg protein ( P<0.05). The levels of AChE activity in tissues exposed to fasted serum were consistently greater, but fell similarly from 1.62±0.10 to 0.97±14 μmol/h/mg protein ( P<0.01), when serum concentrations were increased from 2.5 to 15%. AChE activities were 30% higher in tissues incubated with cycloheximide 10 −3 M ( P<0.02). Unlike AChE, fetal brain enolase activities were unaffected by maternal starvation. In fetal brain cell cultures from fed mothers, enolase fell from 1.85±0.10 to 1.37±0.12 μmol/min/mg protein following exposure to fasted instead of fed serum ( P<0.02). In fetal cultures from starved mothers, enolase activities were depressed similarly from 1.76±0.08 to 1.41±0.09 μmol/min/mg protein when fasted replaced fed serum ( P<0.02). Thus, the fetal brain cell cultures appear to maintain enzymatic realignments imposed by maternal starvation for at least 6 days. In addition, serum from fasted animals has significant growth inhibiting properties manifested by heightened activities of AChE and lower activities of enolase.

Impact of methyl parathion toxicity and eserine inhibition on acetylcholinesterase activity in tissues of the teleost ( Tilapia mossambica) — a correlative study

Acetylcholinesterase (AChE) activity and acetylcholine (ACh) content of muscle, gill, liver and brain tissues of control and methyl parathion-exposed (MPE) fish were determined. In addition, in vitro concentrations of eserine necessary to produce inhibition of AChE equivalent to in vivo inhibition by sublethal amounts of methyl parathion (MP) were also investigated. AChE activity decreased in all tissues, while ACh content showed a corresponding increase. These observations indicate disruption of nerve impulse conduction. The in vitro effect of eserine on AChE activity differed with the type of MP action. These results are discussed in relation to the sensitivity and extent of innervation of various tissues.