Effects of Selective Alkylphosphorylation of Propionylcholinesterase on the Regeneration of Acetylcholinesterase in the Aqueous Soluble Fraction of Superior Cervical Ganglia of the Rat Following Sarin

Abstract: The rates of regeneration of acetylcholinesterase (AChE) and propionylcholinesterase (PrChE) in the supernatants of aqueous homogenates of rat superior cervical ganglia, centrifuged at 100,000 g for 90 min, were determined at 1,3, 6, and 16 h following their inactivation (>90%) by administration of sarin, 2.0μmol/kg i.v. Values were compared with those in animals in which the PrChE was continually suppressed by the repeated, fractional administration of iso-OMPA, in a total dose of 10 or 20 μmol/kg i.p. These doses of iso-OMPA alone produced 96–99% inactivation of PrChE with no detectable effect on AChE. Significant suppression of AChE regeneration by iso-OMPA administration was noted only at 6 h; in contrast with earlier findings in the cat, administration of iso-OMPA alone caused no significant increase in ganglionic AChE activity.     

EFFECTS OF INACTIVATION OF BUTYRYLCHOLINESTERASE ON STEADY STATE AND REGENERATING LEVELS OF GANGLIONIC ACETYLCHOLINESTERASE

The effects of single and repeated injections of tetramonoisopropyl pyrophosphortetramide (iso-OMPA), a selective inactivator of butyrylcholinesterase (BuChE), were studied on the ganglionic and muscular levels of BuChE and acetylcholinesterase (AChE) in cats during the steady state and following the irreversible inactivation of both enzymes by isopropylmethylphosphonofluoridate (sarin). Single intravenous injections of iso-OMPA, 3.0 or 6.0 μmol/kg, produced nearly total inactivation of BuChE with no immediate effect on the AChE of the superior cervical (SCG), stellate (StG), and ciliary (CG) ganglia and inferior oblique (10) muscle; regeneration of BuChE occurred at approximately the same rate in the three ganglia, and at 4–6 days the AChE levels were significantly elevated. When single doses of iso-OMPA were given 1 h following sarin, 2.0 μmol/kg, intravenously, there was a slight increase in the rate of AChE regeneration during the ensuing 2 days. With the repeated injection of iso-OMPA, 3.0 μmol/kg every 48 h, there was a consistent but not statistically significant reduction in AChE regeneration at 4, 6, 12, and 18 days following sarin in all 3 ganglia. Similar treatment with iso-OMPA alone produced significant increases in ganglionic AChE at all these periods excepting the longest. The daily injection of iso-OMPA for 6 days, which maintained ganglionic BuChE at approx 2% of the control values, produced significant reductions in AChE regeneration, but again significant increases in ganglionic AChE levels in cats that did not receive sarin. The IO muscle did not exhibit these effects. A working hypothesis is proposed, that BuChE is a precursor of ganglionic AChE, and that the level of BuChE participates in the regulation of AChE synthesis by inhibition of a preceding rate-limiting step.     

EFFECTS OF PROTECTION OF BUTYRYLCHOLINESTERASE ON REGENERATION OF GANGLIONIC ACETYLCHOLINESTERASE

The regeneration of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was followed in the superior cervical (SCG), stellate (StG), and ciliary (CG) ganglia and inferior oblique (IO) muscle of cats for the 3-day period following their inactivation by isopropylmethylphosphonofluoridate (sarin; 2.0 μmol/kg intravenously), with and without preservation of over half the butyrylcholinesterase activity by the prior intravenous infusion of 10-(α-diethylaminopropionyl) phenothiazine HCl (Astra 1397; 100 or 200 μmol/kg). Rates of regeneration of AChE in the three ganglia exhibited the same sequence as their relative proportions of AChE-containing cholinergic ganglion cells (SCG < StG < CG); no such difference was found in the rates of butyrylcholinesterase regeneration. The mean AChE levels in all three ganglia were higher at 48 h in the cats that had received Astra 1397 (100 μmol/kg) prior to sarin. This finding is interpreted as evidence that BuChE may function as a precursor in the synthesis of AChE.     

Regeneration of Cholinesterases in the Stellate and Normal and Denervated Superior Cervical Ganglia of the Cat Following Inactivation by Sarin

Abstract: Experiments were designed to test the hypothesis that ganglionic butyrylcholinesterase (BuChE) is derived from acetylcholinesterase (AChE). At 5 to 8 days following preganglionic denervation of the right superior cervical ganglion (SCG), cats were given sarin, 2.0 μmol/kg, i.v. At intervals of 1 h and 1, 2, 3, 6, 11, and 22 days later, they were killed, and the AChE and BuChE contents of both SCG and both stellate ganglia (StG) were assayed. The regeneration of AChE in the normal ganglia occurred in two phases: an initial rapid phase, to 25-40% of control activity in 1 day, and a slow phase, to approximately 70% of control activity in 22 days. BuChE reached approximately 85% of control activity in normal SCG and StG at 22 days. In the denervated SCG, AChE activity reached a maximum of approximately 17% of normal at 1 day, the value prior to the administration of sarin, and did not increase appreciably above this subsequently. BuChE activity in the denervated SCG reached approximately 50% of normal ganglia at 22 days. At each interval, its activity approached 55% of that of the contralateral normal SCG, the value found in the denervated SCG prior to the administration of sarin. Hence, the regeneration of BuChE appears to be independent of the presence of AChE in the neuropil. The origin of ganglionic BuChE remains obscure.     

Chicken retinospheroids as developmental and pharmacological in vitro models: acetylcholinesterase is regulated by its own and by butyrylcholinesterase activity

Summary The phylo- and ontogenetically related enzymes butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) are expressed consecutively at the onset of avian neuronal differentiation. In order to investigate their possible co-regulation, we have studied the effect of highly selective inhibitors on each of the cholinesterases with respect to their expression in rotary cultures of the retina (retinospheroids) and stationary cultures of the embryonic chick tectum. Adding the irreversible BChE inhibitor iso-OMPA to reaggregating retinal cells has only slight morphological effects and fully inhibits BChE expression. Unexpectedly, iso-OMPA also suppresses the expression of AChE to 35%–60% of its control activity. Histochemically, this inhibition is most pronounced in fibrous regions. The release of AChE into the media of both types of cultures is inhibited by iso-OMPA by more than 85%. Control experiments show that AChE suppression by the BChE inhibitor is only partially explainable by direct cross-inhibition of iso-OMPA on AChE. In contrast, the treatment of retinospheroids with the reversible AChE inhibitor BW284C51 first accelerates the expression of AChE and then leads to a rapid decay of the spheroids. After injection of BW284C51 into living embryos, we find that AChE is expressed prematurely in cells that normally express BChE. We conclude that the cellular expression of AChE is regulated by the amount of both active BChE and active AChE within neuronal tissues. Thus, direct interaction with classical cholinergic systems is indicated for the seemingly redundant BChE.     

Organophosphorus Compound O,O-Dimethyl-O-(2,2-dichlorovynyl)-Phosphate as Selective Inhibitor for Separate Determination of Acetylcholinesterase and Butyrylcholinesterase Activities in the Roach Rutilus rutilus

A comparative study is carried out on dependence of degree of activity inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of a freshwater bony fish, the roach Rutilus rutilus L., on concentration of organophosphates: O,O-dimethyl-O-(2,2-dichlorovynyl)phosphate (DDVP) and tetraisopropylamidopyrophosphate (iso-OMPA). It has been shown that both in roach and in horse the both inhibitors are selective for BChE in comparison with AChE. Their selectivity degree was 2000-fold and 80-fold, respectively. The ranges of effective DDVP concentrations are overlapped for horse AChE and BChE, while they do not for the roach enzymes. A similar regularity is revealed at action of iso-OMPA. It is established that DDVP has a higher inhibitory potency and selectivity in relation to roach BChE, than iso-OMPA. It is suggested to use DDVP as a new selective inhibitor for separate evaluation of AChE and BChE activities in fish tissues.     

Developmental changes and acetylcholinesterase activity in the metamorphosing brain of Tenebrio molitor: Correlation to ecdysteroid titers

The brain of Tenebrio molitor exhibited marked fluctuations in acetylcholinesterase (AChE) activity throughout metamorphosis. This was true AChE activity, since it was inhibited by high substrate concentrations and by 10 μM of the specific AChE inhibitor BW284C51 [(1,5-bis'4-allyldimethylammoniumphenyl)-pentan-3-one dibromide] but not by iso-OMPA (tetraisopropylpyrophosphoramide), a cholinesterase (but not AChE) inhibitor. The histochemical AChE activity was localized in the neuropile and the nuclear envelope of neurons and glial cells. The enzyme extracted from brains with 1% Triton X-100 and 1 M NaCl sedimented as a single peak in a sucrose density gradient, with a sedimentation coefficient of 5.4S. This single AChE sedimentation peak was mainly due to an amphiphilic dimeric form. AChE activity per brain increased in newly ecdysed pupa. AChE activity per milligram of protein exhibited a peak in the mid-pupa which could be correlated to the increase in ecdysteroid titers. © 1994 Wiley-Liss, Inc.     

Neurotrophic control of 16S acetylcholinesterase from mammalian skeletal muscle in organ culture

The effects of rat obturator nerve extracts on total and 16S acetylcholinesterase (AChE) activity were studied in endplate regions of denervated anterior gracilis muscles maintained in organ culture for 48 hr. The decrease of total AChE activity in cultured muscles was similar to that observed in denervated muscles in vivo. This decrease in activity was partly prevented by addition of either 100 or 200 μl nerve extract (2.7 mg/ml protein) to the nutrient medium. Nerve extract treatment also decreased the release of AChE activity from the muscle into the bathing medium. Conversely, rat serum (20 μl; 90 mg/ml protein) had no effect on total AChE activity in muscle endplates, nor on release of the enzyme by the muscle. The 16S form of AChE was confined to motor endplate muscle regions and its activity was drastically decreased by denervation in both organ culture and in vivo preparations in a comparable manner. Nerve-extract supplemented cultures contained a significantly (p ? 0.001) larger amount of endplate 16S AChE activity (140–145%) than the corresponding controls (100-). Our results suggest that some nerve soluble substance, other than serum contaminants or 16S AChE itself, affects the maintenance of 16S AChE at the neuromuscular junction.     

Effect of Precursors on the Synthesis of Catecholamines and on Neurotransmission in the Superior Cervical Ganglion of the Rat

Abstract: Male Sprague-Dawley rats (325–350 g) were anesthetized with urethane (1.5 g/kg i.p.) and treated with physiological saline, Aspartame (APM; 552 μmol/kg), or tyrosine (Tyr; 552 μmol/kg). Ganglionic transmission and the synthesis of dopamine (DA) and norepinephrine (NE) were measured in the superior cervical ganglion (SCG) following electrical stimulation of the cervical sympathetic trunk (CST). When the CST was stimulated with single pulses, neither APM nor Tyr affected the synthesis of NE or DA. However, in response to low- (5 Hz, 20 s) and high- (20 Hz, 20 s) frequency pulses, the metabolism of DA was increased (p > 0.05), but to the same extent after saline, APM, or Tyr. In rats stimulated with similar low- and high-frequency pulses, the synthesis of NE was increased significantly (p > 0.05) after Tyr, but not after APM or saline. In saline-treated controls, ganglionic transmission was not changed in response to single pulses, or low- or high-frequency stimulation. However, after treatment with APM, ganglionic transmission was depressed significantly (p > 0.01) in response to high-frequency stimulation (single: 0.46 ± 0.09 mV; low: 0.39 ± 0.07 mV; high: 0.27 ± 0.07 mV). After treatment with Tyr, ganglionic transmission was depressed significantly (p > 0.05) in response to both low- and high-frequency stimulation (single: 0.44 ± 0.04 mV; low: 0.22 ±0.12 mV; high: 0.26 ± 0.07 mV). In the nonstimulated SCG, l-3,4-dihydroxyphenylalanine (25 mg/kg) caused a rapid, significant (p > 0.01) increase in the synthesis and metabolism of DA, but not of NE. Treatment with nialamide (200 mg/kg i.p.) followed by electrical stimulation (15 Hz, 15 min) of the CST caused a significant (p > 0.05) increase of both NE and DA in the stimulated SCG. It is concluded that there are both similarities and differences in the regulation of the synthesis of NE and in the modulation of ganglionic transmission after the administration of the precursors APM and Tyr. The results indicate that caution is needed in comparing the neurochemical and neurophysiological effects of different catecholamine precursors.     

Buffalo (Bubalus bubalis) epiphyseal proteins give protection from arsenic and fluoride-induced adverse changes in acetylcholinesterase activity in rats

The objective of this study was to determine the effect of fluoride (F) and arsenic (As) on the activity of acetylcholinesterase (AChE), a critically important nervous system enzyme, and to test the protective role of buffalo epiphyseal (pineal) proteins (BEP) in rats. Arsenic (20 mg/kg BW, intraperitoneally) and F (150 ppm, perorally) were exposed, and BEP was administered intraperitoneally (100 μ g/kg BW) along with F and As to rats for 7 days. As and F exposure significantly (p < 0.05) increased their levels in plasma and decreased the activity of AChE in plasma, RBCs, heart, and brain of rats. Interestingly, As- and F-induced inhibition of AChE activities increased As and F levels in plasma, and organs were significantly (p < 0.05) counteracted by BEP administration. These findings indicate the protective role of buffalo (Bubalus bubalis) epiphyseal proteins on F- and As-induced adverse changes in AChE activity as a candidate biomarker for neurotoxicity in female rats.     

Doxepin and imipramine: Effect on catecholamine inhibition of ganglionic transmission

Doxepin (DOX) and imipramine (IM) administered by close intra-arterial injection (25, 40 and 60 μg/kg) potentiated the inhibitory effect of norepinephrine (NE) on electrically-evoked postganglionic potentials in the superior cervical ganglion of the cat. Dose-response relationships indicated no significant difference between DOX and IM with regard to their effect on NE activity. Potentiation of dopamine (DA)-induced suppression of ganglionic transmission by DOX and IM (25, 40 and 60 μg/kg) was not as pronounced as the potentiation of NE activity by these two antidepressants. Significant potentiation of DA was evident only at the 40 and 60 μg/kg dose levels of DOX and IM. Dose-response relationships indicated that potentiation of DA by DOX was significantly greater than that produced by IM.     

Acetylcholinesterase in the sea urchin Lytechinus variegatus: characterization and developmental expression in larvae

Acetylcholinesterase (AChE) in the echinoid Lytechinus variegatus has been characterized. Kinetic parameters V(max), K(m), K(ss), and b were 2594+/-1048 nmol ATCh hydrolyzed/min/mg tissue wet weight, 185+/-11 microM, 308+/-100 mM, and 0.2, respectively for the substrate ATCh and 17.8+/-6.87 nmol BTCh hydrolyzed/min/mg tissue wet weight, 654+/-424 microM, 36+/-31 mM, and 0.6, respectively for BTCh. Pharmacologic analyses were performed with four inhibitors of cholinesterases, physostigmine, BW284c51, ethopropazine, and iso-OMPA, and yielded IC(50) values of 106+/-4 nM, 718+/-118 nM, 2.57+/-0.6 mM, and >0.0300 M, respectively. Both kinetic and pharmacologic results confirmed the existence of AChE in larval L. variegatus. Dimeric and tetrameric globular forms (determined by velocity sedimentation on sucrose gradients) were present in L. variegatus larvae. Activity of AChE increased significantly as larvae progressed in development from embryos to eight-arm larvae. Acetylcholinesterase activity of F1 larvae derived from sea urchins collected from wild populations and of F1 larvae derived from sea urchins cultured in the laboratory and fed two different diets suggest that the nutritional and/or environmental history of the adult sea urchin affect the developmental progression of AChE activity in the F1 offspring.     

Ultrastructural distribution of cholinesterase activity in the ventral nerve cord of the earthworm Lumbricus terrestris

Summary The fine structure and distribution of cholinesterase (ChE) activity in the ventral nerve cord of the earthworm (Lumbricus terrestris) was studied, using acetyl- and butyrylthiocholine iodides as substrates and iso-OMPA, 284C51 and eserine as inhibitors to discriminate between acetylcholinesterase (AChE) and other cholinesterase (ns.ChE) activities.The earthworm ventral nerve cord exhibits intense ChE activity. Both AChE and ns.ChE were present and they had identical distribution, being located mainly in the supportive glial cells. Most neurones of the ventral nerve cord contained no histochemically demonstrable activity. The ventral giant nerve cells were observed with the electron microscope to exhibit AChE activity. The enzyme was situated in the membranes of the rough-surfaced endoplasmic reticulum and in peculiar lamellated bodies but not in the membranes of the Golgi complex.     

The indomethacin-induced gastric mucosal damage in rats. Effect of gastric acid,acid inhibition,capsaicin-type agents and prostacyclin

In pylorus-ligated rats subcutaneous (sc) pentagastrin (325.5 nmol/kg) or histamine (54.3 μmol/kg), but not the cholinergic linergic agent bethanechol (7.6 or 15.2 μmol/kg), increased gastric mucosal injury by sc indomethacin (55.8 μmol/kg). Intragastric (ig) administration of 0.15 or 0.3 N HCl greatly potentiated injury by sc indomethacin with widespread ulceration, intragastric bleeding and even perforation. The gastric mucosal damage produced by indomethacin plus 0.3 N HCl was reduced by ig capsaicin (3.1–25.1 μM), ig resiniferatoxin (0.38-6.1 μM), by sc atropine (0.15-1.2 μmol/kg) and to a lesser extent by ig prostacyclin (40–267 μM) or sc cimetidine (198.2 μmol/kg). The protective effect of capsaicin or resiniferatoxin was not prevented by atropine or cimetidine treatment. Capsaicin (6.5 mM) enhanced gastric injury by sc or ig indomethacin. Results indicate the importance of early vascular events in the pathogenesis of mucosal injury induced by indomethacin in the stomach and suggest a role for gastric acid in potentiation of such injury. Results further strengthen the idea of a protective role for capsaicin-sensitive sensory nerves in the stomach.     

Kinetic study of the thermal inactivation of cholinesterase enzymes immobilized in solid matrices

The thermal inactivation of immobilized cholinesterase enzymes (ChE) in solid matrices where the protein unfolding is blocked was studied, thus enabling investigation of the kinetics of the inactivation process directly from the native structure to the inactivated state. The thermal inactivation of butyrylcholinesterase (BChE), recombinant human acetylcholinesterase (rHuAChE), and eel acetylcholinesterase (AChE) enzymes was studied in dry films composed of poly(vinyl pyrollidone) (PVP), bovine serum albumin (BSA) and trehalose at 60 degrees -120 degrees C. The kinetics follows a bi-exponential decay equation representing a combination of fast and slow processes. The activation enthalpy DeltaH(#) and the activation entropy DeltaS(#) for each of the three enzymes have been evaluated. The values of DeltaH(#) for the fast process and for the slow process of BChE are 33+/-3, and 28+/-2 kcal/mol, respectively, and the values of DeltaS(#) are 0.84+/-0.04, and -18.2+/-0.5 cal/deg, respectively. The appropriate value of DeltaH(#) for rHuAChE is 26+/-2 Kcal/mol, for both processes and the values of DeltaS(#) are -17.6+/-0.9, and -23.0+/-0.9 cal/deg, respectively. Similarly, the values of DeltaH(#) for eelAChE are 30+/-3, 31+/-1 kcal/mol, and the values of DeltaS(#) are -6.7+/-0.5, -9.1+/-0.2 cal/deg respectively.     

Neurogenic component in the effect of papaverine, drotaverine and bencyclane

Papaverine, drotaverine and bencyclane, drugs considered to have direct action on the smooth muscle, inhibited synaptic transmission in the isolated a sympathetic ganglion of the frog. Their effect depended upon the concentration applied. The ganglionic blocking effect of papaverine and drotaverine in the concentration range from 10(-8) to 10(-6) mol/l was partially antagonized by naloxone and nalorphine as well as by increasing the Ca2+ concentration in the incubation medium. This refers to an activation of specific opiate receptors in the mechanism of ganglionic action of these drugs. The ganglionic effect of bencyclane may be due to its local anaesthetic property, since it was prevented by neither naloxone nor nalorphine, and an increase in the Ca2+ concentration in the medium had no influence on it.     

Effect of lithium and rubidium on the ganglionic inhibitory action of norepinephrine

Close intraarterial infusion of lithium chloride (2 and 4 mEq/kg) transiently suppressed evoked postganglionic potentials in the superior cervical ganglion of the cat; lower doses (0.5 and 1 mEq/kg) had no effect on transmission. Potentiation of the ganglionic inhibitory effect of norepinephrine (NE) occurred at plasma concentrations of lithium equivalent to those found to be therapeutic in man. Concurrent administration of lithium (1 mEq/kg) and doxepin (25 mcg/kg) produced greater facilitation of the ganglionic suppressant effect of NE than either lithium or doxepin alone. Rubidium chloride (0.1, 0.5 and 1 mEq/kg) produced temporary blockade of ganglionic transmission; lower doses (0.05 and 0.075 mEq/kg) did not exhibit a ganglioplegic effect. Reduction of the ganglionic inhibitory activity of NE was observed at each dose level of rubidium. Administration of doxepin (25 mcg/kg) immediately after rubidium (0.075 mEq/kg) significantly reduced the inhibitory effect of the cation on NE activity. These results suggest that, in the cat superior cervical ganglion, lithium may block NE uptake and rubidium may promote NE release.     

Chemical Composition and Anti‐Alzheimer's Disease‐Related Activities of a Functional Oil from the Edible Seaweed Hizikia fusiforme

Cholinergic disorder, oxidative stress, and neuroinflammation play important roles in the pathology of Alzheimer's disease. To explore the healthy potential of the edible seaweed Hizikia fusiforme on this aspect, a functional oil (HFFO) was extracted from this alga and investigated on its constituents by gas chromatography‐mass spectrometry (GC/MS) in this study. Its anti‐Alzheimer's related bioactivities including acetylcholinesterase (AChE) inhibition, antioxidation, and anti‐neuroinflammation were evaluated, traced, and simulated by in vitro and in silico methods. GC/MS analysis indicated that HFFO mainly contained arachidonic acid (ARA), 11,14,17‐eicosatrienoic acid (ETrA), palmitic acid, phytol, etc. HFFO showed moderate AChE inhibition and antioxidant activity. Bioactivity tracing using commercial standards verified that AChE inhibition of HFFO mainly originated from ARA and ETrA, whereas antioxidant activity mainly from ARA. Lineweaver?Burk plots showed that both ARA and ETrA are noncompetitive AChE inhibitors. A molecular docking study demonstrated low CDOCKER interaction energy of ?26.33 kcal/mol for ARA and ?43.70 kcal/mol for ETrA when interacting with AChE and multiple interactions in the ARA (or ETrA)?AChE complex. In the anti‐neuroinflammatory evaluation, HFFO showed no toxicity toward BV‐2 cells at 20 μg/mL and effectively inhibited the production of nitroxide and reduced the level of reactive oxygen species in lipopolysaccharide‐induced BV‐2 cells. The results indicated that HFFO could be used in functional foods for its anti‐Alzheimer's disease‐related activities.     

Synthesis,Spectroscopic Analysis,and in Vitro/in Silico Biological Studies of Novel Piperidine Derivatives Heterocyclic Schiff-Mannich Base Compounds

In the present study, 3-substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones ( S1-8 ) were synthesized by treating 4-hydroxybenzaldehyde ( B ) with eight different 3-substitued-4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones ( T1-8 ) in acetic acid medium, separately. The synthesized Schiff bases ( S ) were reacted with formaldehyde and secondary amine such as 4-piperidinecarboxyamide to afford novel heterocyclic bases. 3-Substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones ( T ) were treated with 4-piperidinecarboxyamide in the presence of formaldehyde to synthesize eight new 1-(4-piperidinecarboxyamide-1-yl - methyl)-3-substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones ( M1-8 ). The structure characterization of compounds was carried out using ¹H-NMR, IR, HR-MS, and ¹³C-NMR spectroscopic methods. The inhibitory properties of the newly synthesized compounds were calculated against the acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione S-transferase (GST) enzymes. Ki values were calculated in the range of 20.06±3.11–36.86±6.17 μM for GST, 17.87±2.91–30.53±4.25 μM for AChE, 9.08±0.69–20.02±2.88 μM for BChE, respectively, Besides, IC₅₀ values were also calculated. Best binding scores of -inhibitors against used enzymes were calculated as −12.095 kcal/mol, −12.775 kcal/mol, and −9.336 kcal/mol, respectively. While 5-oxo-triazole piperidine-4-carboxamide moieties have a critical role in the inhibition of AChE and GST enzymes, hydroxy benzyl moiety is important for BChE enzyme inhibition.     

EFFECTS OF CHRONIC TREATMENT WITH AMINO-OXYACETIC ACID OR SODIUM n-DIPROPYLACETATE ON BRAIN GABA LEVELS AND THE DEVELOPMENT AND REGRESSION OF COBALT EPILEPTIC FOCI IN RATS

Abstract– Acute treatment of cobalt-induced epilepsy in rats with amino-oxyacetic acid (20-60 mg/kg intraperitoneally) resulted in a short period (30-90 min) of epileptic spike suppression. In contrast sodium n -dipropylacetate (100-400 mg/kg intraperitoneally) had no effect on spike frequencies. Chronic treatment of cobalt epileptic rats with amino-oxyacetic acid (2.5-10 mg/kg intraperitoneally daily) or sodium n -dipropylacetate (200-400 mg/kg intraperitoneally daily) elevated brain GABA concentrations significantly and reduced brain glutamate decarboxylase activity relative to control saline-injected cobalt epileptic rats. Brain γ-aminobutyrate aminotransferase activity was significantly reduced by chronic treatment with amino-oxyacetic acid, whereas chronic sodium n -dipropylacetate had no effect on brain γ-aminobutyrate aminotransferase activity although elevating brain GABA. Amino-oxyacetic acid (2.5-10 mg/kg intraperitoneally per day) reduced the frequency of epileptic spikes in the secondary foci of cobalt epileptic rats. The anticonvulsant action of amino-oxyacetic acid was most marked at 5 mg/kg intraperitoneally where a secondary focus failed to develop in treated cobalt epileptic rats. However, there was no simple relationship between the elevation of brain GABA and the anticonvulsant action of amino-oxyacetic acid. Thus focal GABA was higher in rats given intraperitoneal amino-oxyacetic acid (10 mg/kg) but the anticonvulsant action of amino-oxyacetic acid was less marked at this dose. Sodium n -dipropylacetate (200-400 mg/kg intraperitoneally per day) had no long-term anticonvulsant action in this model of epilepsy. It is concluded that the anticonvulsant action of sodium n -dipropylacetate, and probably that of amino-oxyacetic acid, is not likely to be mediated through a mechanism involving elevation of brain GABA.