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Bayard T Storey - One of the best experts on this subject based on the ideXlab platform.
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calcium influx into mouse spermatozoa activated by solubilized mouse zona pellucida monitored with the calcium fluorescent indicator fluo 3 inhibition of the influx by three inhibitors of the zona pellucida induced acrosome reaction tyrphostin a48 pe
Molecular Reproduction and Development, 1994Co-Authors: Janice L Bailey, Bayard T StoreyAbstract:The fluorescent calcium indicator, fluo-3, was loaded as the membrane permeant tetraacetoxymethyl (AM) ester into cauda epididymal mouse sperm at 25 degrees C for 20 min in the absence of bovine serum albumin (BSA) and presence of the dispersant, Pluronic F-127. Excess indicator was removed by two centrifugation washes at 100g for 10 min, a procedure that did not impair sperm motility. Upon resuspension in medium containing 20 mg/ml BSA to promote capacitation, the sperm cells exhibited readily detectable fluorescence uniformly distributed in the cytoplasm. Cell fluorescence was stable over the time of the experiments and was responsive to changes in intracellular calcium concentration, [Ca2+]i. Initial [Ca2+]i was 231 +/- 58 nM (+/- SE, n = 43). Addition of heat-solubilized mouse zonae pellucidae to capacitated sperm increased [Ca2+]i by 106 +/- 19 nM (+/- SE, n = 18), the higher steady-state concentration being reached after 30 min. Subsequent addition of the non-fluorescent calcium ionophore Br-A23187 resulted in a further increase of 114 +/- 18 nM (+/- SE, n = 18), the higher steady-state concentration being reached after 6 min. The increase in [Ca2+]i induced by solubilized zonae pellucidae was largely blocked by 3-Quinuclidinyl Benzilate (QNB), an antagonist of muscarinic receptors that was earlier shown to block the zona pellucida induced acrosome reaction in mouse sperm (Florman and Storey, 1982: Dev Biol 91:121-130). This [Ca2+]i increase was completely blocked by the tyrosine kinase inhibitor, tyrphostin A48, and by the inactivator of G1 proteins, pertussis toxin. At the concentrations at which they blocked the zona pellucida-induced increase in [Ca2+]i, all three inhibitors also blocked the zona pellucida-induced acrosome reaction. These results indicate that [Ca2+]i increase in is an early, if not the initial, reaction in the sequence leading to zona pellucida induced acrosomal exocytosis in mouse sperm. The observation that the three inhibitors, each having a different mode of action, all block the zona pellucida induced [Ca2+]i suggests that the sperm plasma membrane receptors mediating the zona pellucida induced acrosome reaction may function as a complex, whose formation is activated by zona pellucida ligand binding.
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Solubilization and partial purification from mouse sperm membranes of the specific binding activity for 3-Quinuclidinyl Benzilate, a potent inhibitor of the zona pellucida-induced acrosome reaction.
Molecular reproduction and development, 1994Co-Authors: Cynthia R. Ward, Gregory S. Kopf, Bayard T StoreyAbstract:3-Quinuclidinyl Benzilate (QNB), a potent antagonist of muscarinic acetylcholine receptors, has been demonstrated to inhibit specifically the zona pellucida (ZP)-inducud acrosome reaction (AR) in mouse sperm (Florman and Storey, 1982; Dev Biol 91:121–130). In this study we describe the solubilization and partial purification of the mouse sperm QNB binding activity which may represent a component of the putative receptor complex for ZP on the sperm plasma membrane. Sperm membranes were isolated from cell homogenates of washed, capacitated, epididymal mouse sperm. Scatchard plots of QNB binding to these membranes indicated a single class of binding sites with KD = 7.2 nM and Bmax = 8700 sites/cell. These binding characteristics are similar to those seen with QNB binding to whole cells (Florman and Storey, 1982, J Androl 3:157–164). Sperm membranes were solubilized using 1% digitonin/0.2% cholate, and the resultant detergent-soluble fraction possessed QNB binding activity similar to that of intact membranes. The detergent-soluble fraction maintained intact ZP receptor(s)–G protein coupling in that treatment of this fraction with either ZP or mastoparan resulted in a 35% or 65% increase in specific GTPγS binding, respectively. The solubilized membrane preparation was fractionated by gel permeation HPLC. A majority of specific QNB binding activity was confined to one HPLC fraction. Analysis of this fraction by SDS–PAGE revealed a complex of approximately 5 proteins unique to this fraction. The most prominent protein had a Mr of 72 kDa, which is within the Mr range for muscarinic receptors. A protein with Mr = 41 kDa was also present within this fraction. Subsequent pertussis toxin (PTX)-catalyzed ADP-ribosylation of this fraction revealed this protein to be the α subunit of the Gi class of G proteins. Although the QNB binding activity could not be positively identified, we propose that it is contained in one or more of the proteins unique to this fraction and that these proteins, including Gi, may act as part of a sperm receptor complex for the ZP. © 1994 Wiley-Liss, Inc.
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a transient rise in intracellular ca2 is a precursor reaction to the zona pellucida induced acrosome reaction in mouse sperm and is blocked by the induced acrosome reaction inhibitor 3 Quinuclidinyl Benzilate
Molecular Reproduction and Development, 1992Co-Authors: Bayard T Storey, Catherine L Hourani, J B KimAbstract:The acrosome reaction induced by the zona pellucida in mouse sperm has been shown to proceed in two stages experimentally distinguishable by the fluorescent probe chlortetracycline. Entry into the first stage of sperm bound to isolated, structurally intact zonae pellucidae is blocked by the compound 3-Quinuclidinyl Benzilate. In this study, we show, utilizing the fluorescent Ca2+ indicator fluo-3, that the first stage of the zona-induced acrosome reaction is characterized by an increase in intracellular Ca2+, followed by a decrease as the acrosome reaction proceeds. This calcium transient is completely suppressed by 3-Quinuclidinyl Benzilate. We conclude that the Ca2+ transient is induced by the zona pellucida and is required for the zona-induced acrosome reaction. Blockage of this sperm intracellular Ca2+ transient provides a mechanism for the inhibitory action of 3-Quinuclidinyl Benzilate on the zona-induced acrosome reaction in mouse sperm.
Jiri Kassa - One of the best experts on this subject based on the ideXlab platform.
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effects of novel tacrine related cholinesterase inhibitors in the reversal of 3 Quinuclidinyl Benzilate induced cognitive deficit in rats is there a potential for alzheimer s disease treatment
Neuroscience Letters, 2016Co-Authors: Jan Misik, Jan Korabecny, Eugenie Nepovimova, Alzbeta Kracmarova, Jiri KassaAbstract:Inhibitors of cholinesterase are important drugs for therapy of Alzheimer's disease and the search for new modifications is extensive, including dual inhibitors or multi-target hybrid compounds. The aim of the present study was a preliminary evaluation of pro-cognitive effects of newly-developed 7-MEOTA-donepezil like hybrids (compounds no. 1 and 2) and N-alkylated tacrine derivatives (compounds no. 3 and 4) using an animal model of pharmacologically-induced cognitive deficit. Male Wistar rats were subjected to tests of learning and memory in a water maze and step-through passive avoidance task. Cognitive impairment was induced by 3-Quinuclidinyl Benzilate (QNB, 2mgkg(-1)), administered intraperitoneally 1h before training sessions. Cholinesterase inhibitors were administered as a single therapeutic dose following the QNB at 30min at the following dose rates; 1 (25.6mgkg(-1)), 2 (12.3mgkg(-1)), 3 (5.7mgkg(-1)), 4 (5.2mgkg(-1)). The decrease in total path within the 10-swim session (water maze), the preference for target quadrant (water maze) and the entrance latency (passive avoidance) were taken as indicators of learning ability in rats. The effects of novel compounds were compared to that of standards tacrine (5.2mgkg(-1)) and donepezil (2.65mgkg(-1)). QNB significantly impaired spatial navigation as well as fear learning. Generally, the performance of rats was improved when treated with novel inhibitors and this effect reached efficiency of standard donepezil at selected doses. There was a significant improvement in the groups treated with compounds 2 and 3 in all behavioral tasks. The rest of the novel compounds succeed in the passive avoidance test. In summary, the potential of novel inhibitors (especially compounds 2 and 3) was proved and further detailed evaluation of these compounds as potential drugs for Alzheimer's disease treatment is proposed.
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The effects of novel 7-MEOTA-donepezil like hybrids and N-alkylated tacrine analogues in the treatment of Quinuclidinyl Benzilate-induced behavioural deficits in rats performing the multiple T-maze test
Biomedical papers of the Medical Faculty of the University Palacky Olomouc Czechoslovakia, 2015Co-Authors: Jan Misik, Jan Korabecny, Eugenie Nepovimova, Pavla Cabelova, Jiri KassaAbstract:Aims. The number of approved drugs for the clinical treatment of Alzheimer disease remains limited. For this reason, there is extensive search for novel therapies. Of these, cholinesterase inhibitors have some proven benefit in slowing the disease progression and still remain the first-line therapeutic approach. In this study, the pro-cognitive effect of four novel tacrine-related inhibitors was evaluated and compared with the standards, tacrine and donepezil. Methods. Wistar rats trained to perform the multiple T-maze were treated intra-peritoneally with the anticholinergic agent 3-Quinuclidinyl Benzilate (QNB, 2.0 mg/kg), followed 30 min later by another injection containing a therapeutic dose of standard or novel cholinesterase inhibitor. The rats were repeatedly subjected to the multiple T-maze task at several time points following QNB administration (1, 24, 48 and 72 h). The passage time and number of errors were recorded. The inhibitory potential of selected therapeutic doses was assessed in a separate in vivo experiment using a spectrophotometric method. Results. QNB significantly impaired the performance of the rats within 48 h. The four novel cholinesterase inhibitors attenuated the effect of QNB at 1 h, 24 h and 48 h test intervals. The novel compounds resulted in brain cholinesterase inhibition ranging from 5.4 to 11.3 %, and their effect on the QNB-induced deficit recorded in the T-maze performance was comparable to that of the standards or higher at some time points. Conclusion: The best result was achieved with derivative 4, followed by derivatives 2 and 3, suggesting that these compounds could be candidates for the treatment of Alzheimer disease.
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chapter 12 psychotomimetic agent bz 3 Quinuclidinyl Benzilate
Handbook of Toxicology of Chemical Warfare Agents (Second Edition), 2015Co-Authors: Josef Fusek, Jiri Bajgar, Jiri Kassa, Kamil Kuca, Daniel JunAbstract:Agent BZ is the code name for 3-Quinuclidinyl Benzilate (BZ), an anticholinergic ester of glycolic acid. BZ is a psychotomimetic chemical warfare agent described as an anticholinergic hallucinogen. BZ is a competitive inhibitor of the effects of acetylcholine (ACh) acting at the postsynaptic muscarinic receptors in the peripheral nervous system (PNS) and central nervous system (CNS). In the PNS, this inhibition is observed in the muscle, autonomic ganglia, and exocrine glands. BZ’s ability to readily cross the blood–brain barrier causes mental status changes and delirium. BZ is one of the most potent anticholinergic psychotomimetics known with only small doses necessary to produce incapacitation. BZ at single doses of less than 1 mg produces delirium lasting several days. BZ is usually disseminated as an aerosol, and the primary route of absorption is through the respiratory system. Absorption also can occur through the skin or by gastrointestinal tract absorption. The pharmacologic activity of BZ is similar to atropine or scopolamine but with a much longer duration of action. Physicochemical properties and biological effects of BZ are described. The effect is characterized by vegetative symptoms progressing to hallucinations. Distribution of BZ in the body is preferably in the peripheral, followed by the CNS. Its mechanism of effect (toxicodynamics) is based on its interaction with cholinergic receptors in the CNS and PNS, and the resulting lack of a neuromediator—ACh. The antidotal effect against BZ intoxication is based on an increase of ACh levels caused by reversible cholinesterase inhibitors. From this group of compounds, physostigmine was used as the first antidote against BZ. However, physostigmine has a very thin margin between its therapeutic and toxic doses. Therefore, new inhibitors were developed, and acridine derivatives were found to be the most promising. From these compounds, 7-methoxytacrine (7-MEOTA) was the most effective. It is less toxic than physostigmine and tacrine and its central effect is pronounced. It was introduced in the Czech army as an antidote against BZ poisoning.
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A comparison of cholinesterase inhibitors in the treatment of Quinuclidinyl Benzilate-induced behavioural deficit in rats performing the multiple T-maze
Journal of Applied Biomedicine, 2014Co-Authors: Jan Misik, Jiri KassaAbstract:Abstract Cholinesterase inhibitors are beneficial in the treatment of Alzheimer's disease via indirect increase of cholinergic neuro-transmission. The aim of the present study was to evaluate the potency of inhibitors tacrine, rivastigmine and donepezil to reverse cholinergic depletion induced by 3-Quinuclidinyl Benzilate (QNB, 2 mg kg −1 ) in Wistar rats performing the multiple T-maze test. The effect of QNB on retention was compared to the effect of standard amnesic drug, scopolamine, at the dose of 0.3 mg kg −1 . Well-trained rats were treated intra-peritoneally with QNB, followed by another injection containing saline or tacrine (10 mg kg −1 ) or rivastigmine (1.2 mg kg −1 ) or donepezil (2.65 mg kg −1 ) 15 min later. Rats were subjected to the T-maze task 30 min and 24 h following QNB administration. The passage time and number of errors were observed. QNB significantly impaired the performance of rats in both tested times in contrast to short-lasting effect of scopolamine (30 min only). The inhibitors rivastigmine and donepezil significantly attenuated QNB-induced behavioural impairment in the 30 min tests, whereas tacrine failed to have the same effect. Moreover, the performance of tacrine-treated rats was worse due to cholinergic over-stimulation. Beneficial effects of all tested inhibitors including tacrine were evident in the 24 h test.
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cholinergic antagonist 3 Quinuclidinyl Benzilate impact on learning and memory in wistar rats
Behavioural Brain Research, 2014Co-Authors: Jan Misik, Jan Vanek, Kamil Musilek, Jiri KassaAbstract:Abstract 3-Quinuclidinyl Benzilate (QNB) represents a non-selective, competitive antagonist of cholinergic receptors, which has been previously used to generate cognitive deficits in animal models of neurodegenerative disorders. The aim of this study was evaluation of QNB potency for creation of cognitive impairment during the acquisition, consolidation and retrieval stages of learning and memory in rats. Male Wistar rats were subjected to a water maze task with hidden platform and a step-through passive avoidance task. The water maze test was carried out in two separate experiments focused on spatial learning (acquisition test) and long-term spatial memory (retrieval test). QNB doses (0.5, 1.0, 2.0 and 5.0 mg kg−1) were administered to rats intraperitoneally before training sessions (acquisition test) or before probe trial (retrieval test). A QNB dose of 2.0 mg kg−1 was administered to rats in the passive avoidance task before training (acquisition test), immediately post-training (consolidation test) or 24 h pre-retention (retrieval test). QNB significantly impaired the acquisition in the water maze at doses 0.5–5.0 mg kg−1 as well as the acquisition of passive avoidance task. In contrast, consolidation and retrieval were not affected by QNB, indicating that QNB specifically affects the stage of acquisition.
Jan Misik - One of the best experts on this subject based on the ideXlab platform.
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effects of novel tacrine related cholinesterase inhibitors in the reversal of 3 Quinuclidinyl Benzilate induced cognitive deficit in rats is there a potential for alzheimer s disease treatment
Neuroscience Letters, 2016Co-Authors: Jan Misik, Jan Korabecny, Eugenie Nepovimova, Alzbeta Kracmarova, Jiri KassaAbstract:Inhibitors of cholinesterase are important drugs for therapy of Alzheimer's disease and the search for new modifications is extensive, including dual inhibitors or multi-target hybrid compounds. The aim of the present study was a preliminary evaluation of pro-cognitive effects of newly-developed 7-MEOTA-donepezil like hybrids (compounds no. 1 and 2) and N-alkylated tacrine derivatives (compounds no. 3 and 4) using an animal model of pharmacologically-induced cognitive deficit. Male Wistar rats were subjected to tests of learning and memory in a water maze and step-through passive avoidance task. Cognitive impairment was induced by 3-Quinuclidinyl Benzilate (QNB, 2mgkg(-1)), administered intraperitoneally 1h before training sessions. Cholinesterase inhibitors were administered as a single therapeutic dose following the QNB at 30min at the following dose rates; 1 (25.6mgkg(-1)), 2 (12.3mgkg(-1)), 3 (5.7mgkg(-1)), 4 (5.2mgkg(-1)). The decrease in total path within the 10-swim session (water maze), the preference for target quadrant (water maze) and the entrance latency (passive avoidance) were taken as indicators of learning ability in rats. The effects of novel compounds were compared to that of standards tacrine (5.2mgkg(-1)) and donepezil (2.65mgkg(-1)). QNB significantly impaired spatial navigation as well as fear learning. Generally, the performance of rats was improved when treated with novel inhibitors and this effect reached efficiency of standard donepezil at selected doses. There was a significant improvement in the groups treated with compounds 2 and 3 in all behavioral tasks. The rest of the novel compounds succeed in the passive avoidance test. In summary, the potential of novel inhibitors (especially compounds 2 and 3) was proved and further detailed evaluation of these compounds as potential drugs for Alzheimer's disease treatment is proposed.
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The effects of novel 7-MEOTA-donepezil like hybrids and N-alkylated tacrine analogues in the treatment of Quinuclidinyl Benzilate-induced behavioural deficits in rats performing the multiple T-maze test
Biomedical papers of the Medical Faculty of the University Palacky Olomouc Czechoslovakia, 2015Co-Authors: Jan Misik, Jan Korabecny, Eugenie Nepovimova, Pavla Cabelova, Jiri KassaAbstract:Aims. The number of approved drugs for the clinical treatment of Alzheimer disease remains limited. For this reason, there is extensive search for novel therapies. Of these, cholinesterase inhibitors have some proven benefit in slowing the disease progression and still remain the first-line therapeutic approach. In this study, the pro-cognitive effect of four novel tacrine-related inhibitors was evaluated and compared with the standards, tacrine and donepezil. Methods. Wistar rats trained to perform the multiple T-maze were treated intra-peritoneally with the anticholinergic agent 3-Quinuclidinyl Benzilate (QNB, 2.0 mg/kg), followed 30 min later by another injection containing a therapeutic dose of standard or novel cholinesterase inhibitor. The rats were repeatedly subjected to the multiple T-maze task at several time points following QNB administration (1, 24, 48 and 72 h). The passage time and number of errors were recorded. The inhibitory potential of selected therapeutic doses was assessed in a separate in vivo experiment using a spectrophotometric method. Results. QNB significantly impaired the performance of the rats within 48 h. The four novel cholinesterase inhibitors attenuated the effect of QNB at 1 h, 24 h and 48 h test intervals. The novel compounds resulted in brain cholinesterase inhibition ranging from 5.4 to 11.3 %, and their effect on the QNB-induced deficit recorded in the T-maze performance was comparable to that of the standards or higher at some time points. Conclusion: The best result was achieved with derivative 4, followed by derivatives 2 and 3, suggesting that these compounds could be candidates for the treatment of Alzheimer disease.
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A comparison of cholinesterase inhibitors in the treatment of Quinuclidinyl Benzilate-induced behavioural deficit in rats performing the multiple T-maze
Journal of Applied Biomedicine, 2014Co-Authors: Jan Misik, Jiri KassaAbstract:Abstract Cholinesterase inhibitors are beneficial in the treatment of Alzheimer's disease via indirect increase of cholinergic neuro-transmission. The aim of the present study was to evaluate the potency of inhibitors tacrine, rivastigmine and donepezil to reverse cholinergic depletion induced by 3-Quinuclidinyl Benzilate (QNB, 2 mg kg −1 ) in Wistar rats performing the multiple T-maze test. The effect of QNB on retention was compared to the effect of standard amnesic drug, scopolamine, at the dose of 0.3 mg kg −1 . Well-trained rats were treated intra-peritoneally with QNB, followed by another injection containing saline or tacrine (10 mg kg −1 ) or rivastigmine (1.2 mg kg −1 ) or donepezil (2.65 mg kg −1 ) 15 min later. Rats were subjected to the T-maze task 30 min and 24 h following QNB administration. The passage time and number of errors were observed. QNB significantly impaired the performance of rats in both tested times in contrast to short-lasting effect of scopolamine (30 min only). The inhibitors rivastigmine and donepezil significantly attenuated QNB-induced behavioural impairment in the 30 min tests, whereas tacrine failed to have the same effect. Moreover, the performance of tacrine-treated rats was worse due to cholinergic over-stimulation. Beneficial effects of all tested inhibitors including tacrine were evident in the 24 h test.
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cholinergic antagonist 3 Quinuclidinyl Benzilate impact on learning and memory in wistar rats
Behavioural Brain Research, 2014Co-Authors: Jan Misik, Jan Vanek, Kamil Musilek, Jiri KassaAbstract:Abstract 3-Quinuclidinyl Benzilate (QNB) represents a non-selective, competitive antagonist of cholinergic receptors, which has been previously used to generate cognitive deficits in animal models of neurodegenerative disorders. The aim of this study was evaluation of QNB potency for creation of cognitive impairment during the acquisition, consolidation and retrieval stages of learning and memory in rats. Male Wistar rats were subjected to a water maze task with hidden platform and a step-through passive avoidance task. The water maze test was carried out in two separate experiments focused on spatial learning (acquisition test) and long-term spatial memory (retrieval test). QNB doses (0.5, 1.0, 2.0 and 5.0 mg kg−1) were administered to rats intraperitoneally before training sessions (acquisition test) or before probe trial (retrieval test). A QNB dose of 2.0 mg kg−1 was administered to rats in the passive avoidance task before training (acquisition test), immediately post-training (consolidation test) or 24 h pre-retention (retrieval test). QNB significantly impaired the acquisition in the water maze at doses 0.5–5.0 mg kg−1 as well as the acquisition of passive avoidance task. In contrast, consolidation and retrieval were not affected by QNB, indicating that QNB specifically affects the stage of acquisition.
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MILITARY INCAPACITATING AGENT BZ (3-Quinuclidinyl Benzilate) - PAST, PRESENT AND FUTURE
Military Medical Science Letters, 2013Co-Authors: Jan MisikAbstract:Summary The military incapacitating agent BZ (3-Quinuclidinyl Benzilate) is an anticholinergic compound that acts at both, the peripheral and central nervous system. Effects of the agent were discovered during the Cold War and BZ became one of the most potent anticholinergic psychomimetics, characterized by low effective doses causing long-term incapacitation. History, characteristics and potential use of BZ in behavioral research are discussed throughout this review.
J B Kim - One of the best experts on this subject based on the ideXlab platform.
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a transient rise in intracellular ca2 is a precursor reaction to the zona pellucida induced acrosome reaction in mouse sperm and is blocked by the induced acrosome reaction inhibitor 3 Quinuclidinyl Benzilate
Molecular Reproduction and Development, 1992Co-Authors: Bayard T Storey, Catherine L Hourani, J B KimAbstract:The acrosome reaction induced by the zona pellucida in mouse sperm has been shown to proceed in two stages experimentally distinguishable by the fluorescent probe chlortetracycline. Entry into the first stage of sperm bound to isolated, structurally intact zonae pellucidae is blocked by the compound 3-Quinuclidinyl Benzilate. In this study, we show, utilizing the fluorescent Ca2+ indicator fluo-3, that the first stage of the zona-induced acrosome reaction is characterized by an increase in intracellular Ca2+, followed by a decrease as the acrosome reaction proceeds. This calcium transient is completely suppressed by 3-Quinuclidinyl Benzilate. We conclude that the Ca2+ transient is induced by the zona pellucida and is required for the zona-induced acrosome reaction. Blockage of this sperm intracellular Ca2+ transient provides a mechanism for the inhibitory action of 3-Quinuclidinyl Benzilate on the zona-induced acrosome reaction in mouse sperm.
Jana Žďárová Karasová - One of the best experts on this subject based on the ideXlab platform.
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3 Quinuclidinyl Benzilate agent bz toxicokinetics in rats
Basic & Clinical Pharmacology & Toxicology, 2021Co-Authors: Alžběta Dlabková, David Herman, Lenka Cechova, Milos Hroch, Nela Vanova, Jana Žďárová KarasováAbstract:3-Quinuclidinyl Benzilate (BZ) ranks among incapacitating military warfare agents. It acts as a competitive inhibitor on muscarinic receptors leading to non-lethal mental impairment. The present study aimed to investigate toxicokinetics of BZ in rats. Moreover, BZ can be exploited to produce a pharmacological model of Alzheimer's disease; thus, this paper focuses mainly on the BZ distribution to the brain. Wistar rats were administered i.p. with BZ (2 and 10 mg/kg). The BZ concentration was determined using LC-MS/MS in plasma, urine, bile, brain, kidney and liver. The sample preparation was based on a solid phase extraction (liquids) or protein precipitation (organ homogenates). The plasma concentration peaked at 3 min (204.5 ± 55.4 and 2185.5 ± 465.4 ng/ml). The maximal concentration in the brain was reached several minutes later. Plasma elimination half-life was 67.9 ± 3.4 in the 2 mg/kg group and 96.6 ± 27.9 in the 10 mg/kg group. BZ concentrations remained steady in the brain, with slow elimination (t1/2 506.9 ± 359.5 min). Agent BZ is excreted mainly via the urine. Steady BZ concentration in the brain could explain the previously published duration of the significant impairment in passive avoidance tasks in rats after an injection of BZ.
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In vitro and in vivo metabolism of 3-Quinuclidinyl Benzilate by high-resolution mass spectrometry
Journal of pharmaceutical and biomedical analysis, 2020Co-Authors: Martin Uher, Martin Mžik, Jana Žďárová Karasová, David Herman, Lenka Cechova, Alžběta Dlabková, Alena Mrkvicova, Milos HrochAbstract:3-Quinuclidinyl Benzilate (QNB) is an anticholinergic compound that affects the nervous system. Its hallucinogenic action has led to its potential utility as an incapacitating warfare agent, and it is listed in Schedule 2 by the Organization for the Prohibition of Chemical Weapons. Although this compound has been known for a long time, limited information is available regarding its metabolism and mass spectrometric data of the metabolites, the information that could facilitate the identification of QNB in case of suspected intoxication. To the best of our knowledge, the analytical methods previously described in the literature are based on outdated procedures, which may result in a significantly lower number of observable metabolites. The aim of this work was to obtain deeper insight into QNB biotransformation using a combination of in vitro and in vivo approach. The development of a suitable method for the separation and detection of metabolites using mass spectrometry together with the identification of reliable diagnostic fragments for the unambiguous identification of QNB metabolites in the different biological matrices are also presented in this work. A screening of rat plasma, urine and tissue homogenates revealed 26 new metabolites related to the cytochrome P450 biotransformation pathway, which involves N-oxidation and hydroxylation(s) followed by O-methylation and O-glucuronosylation within phase II of the metabolism. A study showed that the brain is not metabolically active in the case of QNB and that the metabolites do not cross the blood-brain barrier; thus, the toxicodynamic effects are due to QNB itself. In addition, in vitro experiments performed using isolated human liver microsomes revealed N-oxidation as the principal metabolic pathway in human tissue. In light of current global events, the abuse of QNB by terrorists or para-military groups is a real possibility, and our findings may improve the detection systems used in laboratories involved in postexposure investigations.
