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Latif S, Kang YS. Protective Effects of Choline against Inflammatory Cytokines and Characterization of Transport in Motor Neuron-like Cell Lines (NSC-34). Pharmaceutics 2022; 14:2374. [PMID: 36365192 PMCID: PMC9699384 DOI: 10.3390/pharmaceutics14112374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 02/02/2024] Open
Abstract
Choline, a component of the neurotransmitter acetylcholine, is essential for nervous system functions, brain development, and gene expression. In our study, we investigated the protective effect and transport characteristics of choline in amyotrophic lateral sclerosis (ALS) model cell lines. We used the wild-type (WT) motor neuron-like hybrid cell line (NSC-34/hSOD1WT) as a control and the mutant-type (MT; NSC-34/hSOD1G93A) as a disease model. The uptake of [3H]choline was time-, pH-, and concentration-dependent. [3H]Choline transport was sodium-dependent, and, upon pretreatment with valinomycin, induced membrane depolarization. Gene knockdown of Slc44a1 revealed that choline-like transporter 1 (CTL1) mediates the transport of choline. In NSC-34 cell lines, the specific choline transporter inhibitor, hemicholinium-3 demonstrated significant inhibition. Donepezil and nifedipine caused dose-dependent inhibition of [3H]choline uptake by the MT cell line with minimal half inhibitory concentration (IC50) values of 0.14 mM and 3.06 mM, respectively. Four-day pretreatment with nerve growth factor (NGF) resulted in an inhibitory effect on [3H]choline uptake. Choline exerted protective and compensatory effects against cytokines mediators. Hence, the choline transport system CLT1 may act as a potential target for the delivery of novel pharmacological drugs, and the combination of drugs with choline can help treat symptoms related to ALS.
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Affiliation(s)
| | - Young-Sook Kang
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Sookmyung Women’s University, 100 Cheongpa-ro 47-gil, Yongsan-gu, Seoul 04310, Korea
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2
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Artiukhov AV, Aleshin VA, Karlina IS, Kazantsev AV, Sibiryakina DA, Ksenofontov AL, Lukashev NV, Graf AV, Bunik VI. Phosphonate Inhibitors of Pyruvate Dehydrogenase Perturb Homeostasis of Amino Acids and Protein Succinylation in the Brain. Int J Mol Sci 2022; 23:13186. [PMID: 36361974 PMCID: PMC9655319 DOI: 10.3390/ijms232113186] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 10/21/2023] Open
Abstract
Mitochondrial pyruvate dehydrogenase complex (PDHC) is essential for brain glucose and neurotransmitter metabolism, which is dysregulated in many pathologies. Using specific inhibitors of PDHC in vivo, we determine biochemical and physiological responses to PDHC dysfunction. Dose dependence of the responses to membrane-permeable dimethyl acetylphosphonate (AcPMe2) is non-monotonous. Primary decreases in glutathione and its redox potential, methionine, and ethanolamine are alleviated with increasing PDHC inhibition, the alleviation accompanied by physiological changes. A comparison of 39 brain biochemical parameters after administration of four phosphinate and phosphonate analogs of pyruvate at a fixed dose of 0.1 mmol/kg reveals no primary, but secondary changes, such as activation of 2-oxoglutarate dehydrogenase complex (OGDHC) and decreased levels of glutamate, isoleucine and leucine. The accompanying decreases in freezing time are most pronounced after administration of methyl acetylphosphinate and dimethyl acetylphosphonate. The PDHC inhibitors do not significantly change the levels of PDHA1 expression and phosphorylation, sirtuin 3 and total protein acetylation, but increase total protein succinylation and glutarylation, affecting sirtuin 5 expression. Thus, decreased production of the tricarboxylic acid cycle substrate acetyl-CoA by inhibited PDHC is compensated by increased degradation of amino acids through the activated OGDHC, increasing total protein succinylation/glutarylation. Simultaneously, parasympathetic activity and anxiety indicators decrease.
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Affiliation(s)
- Artem V. Artiukhov
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Department of Biochemistry, Sechenov University, 105043 Moscow, Russia
| | - Vasily A. Aleshin
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Department of Biochemistry, Sechenov University, 105043 Moscow, Russia
| | - Irina S. Karlina
- Department of Clinical Medicine, Sechenov University, 105043 Moscow, Russia
| | - Alexey V. Kazantsev
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Chemistry, Lomonosov Moscow State University, 119234 Moscow, Russia
| | | | - Alexander L. Ksenofontov
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Nikolay V. Lukashev
- Faculty of Chemistry, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Anastasia V. Graf
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Victoria I. Bunik
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Department of Biochemistry, Sechenov University, 105043 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia
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Tanaka-Kanegae R, Hamada K. A novel in vitro assay model developed to measure both extracellular and intracellular acetylcholine levels for screening cholinergic agents. PLoS One 2021; 16:e0258420. [PMID: 34637466 PMCID: PMC8509891 DOI: 10.1371/journal.pone.0258420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 09/27/2021] [Indexed: 11/24/2022] Open
Abstract
Background Cholinergic neurons utilize choline (Ch) to synthetize acetylcholine (ACh) and contain a high-affinity Ch transporter, Ch acetyltransferase (ChAT), ACh receptors, and acetylcholinesterase (AChE). As the depletion or malfunction of each component of the cholinergic system has been reported in patients with dementia, many studies have sought to evaluate whether treatment candidates affect each of the cholinergic components. The associated changes in the cholinergic components may be reflected by intra- or extra-cellular ACh levels, with an increase in extracellular ACh levels occurring following AChE inhibition. We hypothesized that increases in intracellular ACh levels can be more sensitively detected than those in extracellular ACh levels, thereby capturing subtle effects in the cholinergic components other than AChE. The objective of this study was to test this hypothesis. Methods We developed an in vitro model to measure both extracellular and intracellular ACh levels using the human cholinergic neuroblastoma cell line, LA-N-2, which have been reported to express Ch transporter, ChAT, muscarinic ACh receptor (mAChR), and AChE. With this model, we evaluated several drug compounds and food constituents reported to improve cholinergic function through various mechanisms. In addition, we conducted western blotting to identify the subtype of mAChR that is expressed on the cell line. Results Our cell-based assay system was capable of detecting increases in extracellular ACh levels induced by an AChE inhibitor at relatively high doses, as well as increases in intracellular ACh levels following the administration of lower AChE-inhibitor doses and an mAChR agonist. Moreover, increases in intracellular ACh levels were observed even after treatment with food constituents that have different mechanisms of action, such as Ch provision and ChAT activation. In addition, we revealed that LA-N-2 cells expressed mAChR M2. Conclusion The findings support our hypothesis and indicate that the developed assay model can broadly screen compounds from drugs to food ingredients, with varying strengths and mechanisms of action, to develop treatments for ACh-relevant phenomena, including dementia and aging-related cognitive decline.
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Affiliation(s)
- Ryohei Tanaka-Kanegae
- Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical Co., Ltd., Saga, Japan
- * E-mail:
| | - Koichiro Hamada
- Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical Co., Ltd., Saga, Japan
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Bergman HM, Lundin E, Andersson M, Lanekoff I. Quantitative mass spectrometry imaging of small-molecule neurotransmitters in rat brain tissue sections using nanospray desorption electrospray ionization. Analyst 2016; 141:3686-95. [DOI: 10.1039/c5an02620b] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nano-DESI mass spectrometry imaging enables quantitative imaging of small-molecule neurotransmitters which are essential to the function of the nervous system.
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Affiliation(s)
| | - Erik Lundin
- Department of Chemistry-BMC
- Uppsala University
- Uppsala
- Sweden
| | - Malin Andersson
- Department of Pharmaceutical Biosciences
- Uppsala University
- Uppsala
- Sweden
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5
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Rae CD. A Guide to the Metabolic Pathways and Function of Metabolites Observed in Human Brain 1H Magnetic Resonance Spectra. Neurochem Res 2013; 39:1-36. [PMID: 24258018 DOI: 10.1007/s11064-013-1199-5] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 12/20/2022]
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Hall H, Cuellar-Baena S, Denisov V, Kirik D. Development of NMR spectroscopic methods for dynamic detection of acetylcholine synthesis by choline acetyltransferase in hippocampal tissue. J Neurochem 2012; 124:336-46. [DOI: 10.1111/jnc.12025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/18/2012] [Accepted: 09/19/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Hélène Hall
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S); BMC D11; Department of Experimental Medical Science; Lund University; Lund Sweden
| | - Sandra Cuellar-Baena
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S); BMC D11; Department of Experimental Medical Science; Lund University; Lund Sweden
| | - Vladimir Denisov
- Lund University BioImaging Center; BMC D11; Lund University; Lund Sweden
| | - Deniz Kirik
- Brain Repair And Imaging in Neural Systems (B.R.A.I.N.S); BMC D11; Department of Experimental Medical Science; Lund University; Lund Sweden
- Lund University BioImaging Center; BMC D11; Lund University; Lund Sweden
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Zampolini M, Tarducci R, Gobbi G, Franceschini M, Todeschini E, Presciutti O. Localized in vivo H-MRS of traumatic brain injury. Eur J Neurol 2011. [DOI: 10.1111/j.1468-1331.1997.tb00343.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Dahlstrom AB. Fast intra-axonal transport: Beginning, development and post-genome advances. Prog Neurobiol 2010; 90:119-45. [DOI: 10.1016/j.pneurobio.2009.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/23/2009] [Accepted: 11/23/2009] [Indexed: 01/02/2023]
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Choline availability and acetylcholine synthesis in the hippocampus of acetylcholinesterase-deficient mice. Neurochem Int 2007; 52:972-8. [PMID: 18023504 DOI: 10.1016/j.neuint.2007.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 10/08/2007] [Accepted: 10/10/2007] [Indexed: 11/21/2022]
Abstract
Mice deficient for acetylcholinesterase (AChE) have strongly increased extracellular levels of acetylcholine (ACh) in the dorsal hippocampus [Hartmann, J., Kiewert, C., Duysen, E.G., Lockridge, O., Greig, N.H., Klein, J., 2007. Excessive hippocampal acetylcholine levels in acetylcholinesterase-deficient mice are moderated by butyrylcholinesterase activity. J. Neurochem. 100, 1421-1429]. Using microdialysis, we found that increased ACh levels are accompanied by decreased levels of extracellular choline which were 1.60 microM in AChE-deficient mice and 4.36 microM in wild-type mice. Addition of choline (10 microM) to the perfusion fluid, while ineffective in wild-type animals, more than doubled extracellular ACh levels in AChE-deficient mice. High-affinity choline uptake (HACU), as measured ex vivo in corticohippocampal synaptosomes, was more than doubled in AChE-deficient mice. Inhibition of HACU by hemicholinium-3 (HC-3) in vivo reduced extracellular levels of ACh by 60% in wild-type mice but by more than 90% in AChE-deficient mice. Decreased ACh levels caused by infusion of HC-3 or tetrodotoxin (TTX) were accompanied by increased levels of free choline. Infusion of scopolamine (1 microM) caused a fivefold increase of ACh levels in wild-type animals but only a 50% increase in AChE-deficient mice. In conclusion, absence of AChE causes dynamic changes in the ratio of choline to ACh. High levels of extracellular ACh are accompanied by reduced levels of extracellular choline, and ACh release becomes strongly dependent on choline availability. Similar changes may take place in patients chronically exposed to AChE inhibitors.
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10
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Zhang Y, Yamada H, Bibevski S, Zhuang S, Mowrey KA, Wallick DW, Oh S, Mazgalev TN. Chronic atrioventricular nodal vagal stimulation: first evidence for long-term ventricular rate control in canine atrial fibrillation model. Circulation 2005; 112:2904-11. [PMID: 16260638 DOI: 10.1161/circulationaha.105.568832] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND We have previously demonstrated that selective atrioventricular nodal (AVN) vagal stimulation (AVN-VS) can be used to control ventricular rate during atrial fibrillation (AF) in acute experiments. However, it is not known whether this approach could provide a long-term treatment in conscious animals. Thus, this study reports the first observations on the long-term efficacy and safety of this novel approach to control ventricular rate during AF in chronically instrumented dogs. METHODS AND RESULTS In 18 dogs, custom-made bipolar patch electrodes were sutured to the epicardial AVN fat pad for delivery of selective AVN-VS by a subcutaneously implanted nerve stimulator (pulse width 100 micros or 1 ms, frequency 20 or 160 Hz, amplitude 6 to 10 V). Fast-rate right atrial pacing (600 bpm) was used to induce and maintain AF. ECG, blood pressure, and body temperature were monitored telemetrically. One week after the induction of AF, AVN-VS was delivered and maintained for at least 5 weeks. It was found that AVN-VS had a consistent effect on ventricular rate slowing (on average 45+/-13 bpm) over the entire period of observation. Echocardiography showed improvement of cardiac indices with ventricular rate slowing. AVN-VS was well tolerated by the animals, causing no signs of distress or discomfort. CONCLUSIONS Beneficial long-term ventricular rate slowing during AF can be achieved by implantation of a nerve stimulator attached to the epicardial AVN fat pad. This novel concept is an attractive alternative to other methods of rate control and may be applicable in a selected group of patients.
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Affiliation(s)
- Youhua Zhang
- Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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11
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Schuvailo ON, Dzyadevych SV, El'skaya AV, Gautier-Sauvigné S, Csöregi E, Cespuglio R, Soldatkin AP. Carbon fibre-based microbiosensors for in vivo measurements of acetylcholine and choline. Biosens Bioelectron 2005; 21:87-94. [PMID: 15967355 DOI: 10.1016/j.bios.2004.09.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 09/22/2004] [Accepted: 09/22/2004] [Indexed: 10/26/2022]
Abstract
This report describes technical improvements to the manufacture of a carbon fibre electrode for the stable and sensitive detection of H2O2 (detection limit at 0.5 microM). This electrode was also modified through the co-immobilisation of acetylcholinesterase (AChE) and/or choline oxidase (ChOx) in a bovine serum albumin (BSA) membrane for the development of a sensor for in vivo measurements of acetylcholine and choline. Amperometric measurements were performed using a conventional three-electrode system forming part of a flow-injection set-up at an applied potential of 800-1100 mV relative to an Ag/AgCl reference electrode. The optimised biosensor obtained was reproducible and stable, and exhibited a detection limit of 1 microM for both acetylcholine and choline. However, due to the high operating potential used, the biosensor was prone to substantial interference from other electroactive compounds, such as ascorbic acid. Therefore, in a further step, a mediated electron transfer approach was used that incorporated horseradish peroxidase into an osmium-based redox hydrogel layered onto the active surface of the electrode. Afterwards, a Nafion layer and a coating containing AChE and/or ChOx co-immobilised in a BSA membrane were successively deposited. This procedure further increased the selectivity of the biosensor, when operated in the same flow-injection system but at an applied potential of -50 mV relative to an Ag/AgCl reference electrode. The sensor exhibited good selectivity and a high sensitivity over a concentration range (0.3-100 microM) suitable for the measurement of choline and acetylcholine in vivo.
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Affiliation(s)
- O N Schuvailo
- Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics of Ukrainian NAS, 150 Zabolotnogo Street, Kyiv 03143, Ukraine
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12
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Meier-Ruge W, Kolbe M, Sattler J. Investigations of the cholinergic deficit hypothesis in the hippocampus of the aged rat brain with physostigmine and scopolamine. Arch Gerontol Geriatr 2005; 12:239-51. [PMID: 15374451 DOI: 10.1016/0167-4943(91)90031-k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/1990] [Accepted: 12/13/1990] [Indexed: 11/24/2022]
Abstract
Using histochemically demonstrated acetylcholinesterase activity and (14)C-2-deoxyglucose uptake as the respective indices, a study was set up to determine whether cerebral (hippocampal) metabolism was stimulated by a cholinergic agonist and/or inhibited by a cholinergic antagonist. For this 36 12-month-old (adult) and 48 27-month-old (aged) Fischer 344 rats were given intraperitoneal injections of physostigmine 0.05, 0.1 or 0.2 mg/kg or scopolamine 0.01, 0.03 or 0.1 mg/kg for 5 days. In the aged rats there was a slight increase in acetylcholinesterase activity after physostigmine but no convincing evidence of enhanced (14)C-2-deoxyglucose uptake. In neither age group was glucose uptake significantly reduced by scopolamine; it was in fact increased, as was - slightly but significantly - acetylcholinesterase activity. Findings for acetylcholinesterase activity and (14)C-2-deoxyglucose uptake in aged Fischer 344 rats thus do not provide firm corroboration of physostigmine-induced stimulation of mental performance found in behavioural studies, while scopolamine did not adversely affect the hippocampal variables studied. It is concluded that cholinergic agents such as physostigmine and scopolamine have only a marginal effect on the functional and metabolic deficits associated with cerebral aging.
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Affiliation(s)
- W Meier-Ruge
- Division of Gerontological Brain Research, Institute of Pathology, Basle University Medical School, Basle, Switzerland
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13
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O'Regan S, Meunier FM. Selection and characterization of the choline transport mutation suppressor from Torpedo electric lobe, CTL1. Neurochem Res 2003; 28:551-5. [PMID: 12675144 DOI: 10.1023/a:1022877524469] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The presumptive choline transporter, CTL1, was initially identified through functional complementation of a triple yeast mutant (ctr ise URA3delta) with deficiencies in both choline transport and choline neosynthesis under selective conditions that cause perturbations in membrane synthesis and growth. After transformation of these yeasts with a heterologous yeast expression library made from Torpedo electric lobe cDNAs, several colonies showed increased growth but only one clone increased the accumulation of external choline. The corresponding full-length cDNA was isolated and encodes a protein with 10 transmembrane domains. Northern analysis of Torpedo mRNA indicates that CTL1 is expressed at high levels in the spinal cord and brain. In Xenopus oocytes, Torpedo CTL1 expression was associated with the appearance of sodium independent high-affinity choline uptake. We propose that CTL1 plays a role in providing choline for membrane synthesis in the nervous system.
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Affiliation(s)
- Seana O'Regan
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, 91198 Gif-sur-Yvette, France.
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14
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Schuvailo OM, Danyleyko LV, Arkhypova VM, Dzyadevych SV, Elskaya AV, Cespuglio R, Soldatkin AP. Development of microbiosensors based on carbon fibres for in vivo determination of glucose, acetylcholine and choline. ACTA ACUST UNITED AC 2002. [DOI: 10.7124/bc.00062c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- O. M. Schuvailo
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - L. V. Danyleyko
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - V. M. Arkhypova
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - S. V. Dzyadevych
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - A. V. Elskaya
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - R. Cespuglio
- Claude Bernard University. Department of Experimental Medicine. Lyon
| | - A. P. Soldatkin
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
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Fukatsu T, Miyake-Takagi K, Nagakura A, Omino K, Okuyama N, Ando T, Takagi N, Furuya Y, Takeo S. Effects of nefiracetam on spatial memory function and acetylcholine and GABA metabolism in microsphere-embolized rats. Eur J Pharmacol 2002; 453:59-67. [PMID: 12393060 DOI: 10.1016/s0014-2999(02)02360-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study aimed to determine whether nefiracetam, N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, a cognition enhancer, has an effect on learning and memory function in sustained cerebral ischemia, and whether the effect, if any, may accompany modification of the cholinergic or gamma-aminobutyric acid (GABA)ergic system, which are conceived to be involved in the learning and memory function, in the ischemic brain. Sustained cerebral ischemia was induced by the injection of 700 microspheres into the right hemisphere of the rat. The animals were treated once daily with 10 mg/kg nefiracetam p.o. from 15 h after the operation to either 10 days for the water maze study, or 3 or 5 days after the operation for neurochemical examination. Microsphere-embolized rats showed stroke-like symptoms 15 h after the operation and lengthened the escape latency in the water maze task on days 7-10, suggesting a spatial learning dysfunction. The delayed treatment did not reduce the stroke-like symptoms, but effectively shortened the escape latency. The animals at days 3 and 5 after the operation showed decreases in acetylcholine content and choline acetyltransferase activity, which were not prevented by nefiracetam. The microsphere-embolized rats showed decreases in GABA content and glutamic acid decarboxylase activity. The delayed treatment appreciably restored GABA content in the hippocampus on day 5 and reversed glutamic acid decarboxylase activity in both brain regions on day 5. These results suggest that the GABAergic activity rather than the cholinergic activity may be, at least in part, involved in the pharmacological effects of nefiracetam in the ischemic brain.
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Affiliation(s)
- Tomoko Fukatsu
- Department of Pharmacology, Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392, Japan
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Crowe AP, Lockman PR, Abbruscato TJ, Allen DD. Novel choline transport characteristics in Caco-2 cells. Drug Dev Ind Pharm 2002; 28:773-81. [PMID: 12236063 DOI: 10.1081/ddc-120005623] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
UNLABELLED Choline transport is characterized by sodium-dependent high-affinity, sodium-independent low-affinity, and sodium-independent blood-brain barrier transport mechanisms. Each defined mechanism has specific characteristics with regard to affinity for choline, transport capacity, and inhibition by hemicholinium. The purpose of this study is to determine the characteristics of choline transport across Caco-2 monolayers. METHODS Choline transport across Caco-2 cell monolayers was determined in both the apical to basal direction and the opposite direction. Further, the determination of calcium dependence and specific inhibitors was made. Determination of the apparent permeability of choline was calculated by established methods. RESULTS The apical to basal Caco-2 permeability coefficient is 11.11 +/- 0.33 x 10(-6) cm/sec with 21.3% of the choline associating with the cells. Meanwhile the basal to apical value is approximately 50% less (5.55 +/- 0.14 x 10(-6) cm/sec), suggesting an active apical to basal transport mechanism. Choline transport in this system was inhibited by nifedipine (82%), verapamil (80%), EGTA (36%), and cyclosporin (15%). CONCLUSIONS Choline transport across Caco-2 cells is demonstrated to be active and both pH- and Ca(2+)-dependent. Furthermore, choline transport across Caco-2 monolayers has unique characteristics when compared to traditional choline transport models.
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Affiliation(s)
- A P Crowe
- Division of Health Sciences, School of Pharmacy, Curtin University of Technology, Perth, Western Australia 6845
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Buchholzer ML, Dvorak C, Chatterjee SS, Klein J. Dual modulation of striatal acetylcholine release by hyperforin, a constituent of St. John's wort. J Pharmacol Exp Ther 2002; 301:714-9. [PMID: 11961077 DOI: 10.1124/jpet.301.2.714] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Extracts of the medicinal plant St. John's wort (Hypericum perforatum) are widely used for the treatment of mild to moderate depression. Hyperforin, a constituent of St. John's wort, is known to inhibit the sodium-dependent uptake of catecholamines and amino acids into synaptic nerve endings, probably by interference with mechanisms controlling the synaptic sodium concentration. Because de novo synthesis of acetylcholine (ACh) is dependent on sodium-dependent high-affinity choline uptake, we studied the effect of hyperforin on choline (Ch) uptake in vitro and on striatal ACh release in vivo using microdialysis. In rat brain synaptosomes, hyperforin inhibited high-affinity choline uptake with an IC(50) of 8.5 microM, whereas low-affinity uptake was not affected. Local infusion of hyperforin (100 microM) via the dialysis probe caused a delayed reduction of ACh release and a concomitant increase of Ch levels. Infusion of a lower concentration of hyperforin (10 microM), however, increased striatal ACh release and lowered Ch levels. Systemic administration of hyperforin (1-10 mg/kg i.p.) led to therapeutic plasma levels of hyperforin and caused a significant elevation of striatal ACh release. Behavioral testing revealed a reduction of locomotor activity in mice treated with high-dose (10 mg/kg) hyperforin. We conclude that low doses of hyperforin stimulate striatal ACh release by an unknown mechanism, whereas high doses inhibit synaptic choline uptake and ACh release. The results are discussed with respect to the therapeutic use of St. John's wort in patients with neurodegenerative disorders.
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Wallick DW, Zhang Y, Tabata T, Zhuang S, Mowrey KA, Watanabe J, Greenberg NL, Grimm RA, Mazgalev TN. Selective AV nodal vagal stimulation improves hemodynamics during acute atrial fibrillation in dogs. Am J Physiol Heart Circ Physiol 2001; 281:H1490-7. [PMID: 11557537 DOI: 10.1152/ajpheart.2001.281.4.h1490] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the atrioventricular node (AVN) plays a vital role in blocking many of the atrial impulses from reaching the ventricles during atrial fibrillation (AF), a rapid irregular ventricular rate nevertheless persists. The goals of the present study were to explore the feasibility of novel epicardial selective vagal nerve stimulation for slowing of the ventricular rate during AF and to characterize the hemodynamic benefits in vivo. Electrophysiological-echocardiographic experiments were performed on 11 anesthetized open-chest dogs. Hemodynamic measurements were performed during three distinct periods: 1) sinus rate, 2) AF, and 3) AF with vagal nerve stimulation. AF was associated with significant deterioration of all measured parameters (P < 0.025). The vagal nerve stimulation produced slowing of the ventricular rate, significant reversal of the pressure and contractile indexes (P < 0.025), and a sharp reduction in one-half of the abortive ventricular contractions. The present study provides comprehensive evidence that slowing of the ventricular rate during AF by selective ganglionic stimulation of the vagal nerves that innervate the AVN successfully improved the hemodynamic responses.
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Affiliation(s)
- D W Wallick
- Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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19
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Smith YR, Zubieta JK. Neuroimaging of aging and estrogen effects on central nervous system physiology. Fertil Steril 2001; 76:651-9. [PMID: 11591393 DOI: 10.1016/s0015-0282(01)01985-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To review the literature on neuroimaging studies focusing on gender differences in the aging process and on the effects of postmenopausal estrogen use on the brain. DESIGN Pertinent studies were identified through a computer MEDLINE search. References of selected articles were hand-searched for additional citations. CONCLUSION(S) The current literature suggests that estrogen replacement may decrease brain white matter lesions, increase cerebral blood flow, alter regional brain activation patterns during cognitive processing, and have modulatory effects on various neurotransmitter systems. Overall, this points to a functional plasticity in higher order brain processing that can be altered by gonadal steroids.
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Affiliation(s)
- Y R Smith
- University of Michigan, Department of Obstetrics and Gynecology, Women's Hospital, Ann Arbor, Michigan 48109-0276, USA.
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20
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Abstract
Choline is an important membrane phospholipid constituent and a neurotransmitter precursor that is minimally synthesized in brain. The long-term maintenance of brain choline concentration is dependent on uptake from plasma, which occurs via saturable transporter at the blood-brain barrier. Previous studies have suggested that brain choline uptake declined with age. To reevaluate this, brain choline uptake in 3, 12, 24, and 28-month-old Fischer-344 rats was evaluated using the in situ brain perfusion technique. Minimal differences were found with uptake parameters differing by approximately 10% between aged and adult rats for tracer levels while similar trends were observed at higher choline concentrations. Further, estimated Vmax and Km values differed by <30% between the groups. The results suggest that blood-brain barrier choline uptake changes minimally with aging in the rat.
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Affiliation(s)
- D D Allen
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University HSC, Amarillo 79106-1712, USA.
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21
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Sawada N, Takanaga H, Matsuo H, Naito M, Tsuruo T, Sawada Y. Choline uptake by mouse brain capillary endothelial cells in culture. J Pharm Pharmacol 1999; 51:847-52. [PMID: 10467961 DOI: 10.1211/0022357991773050] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Choline, a precursor of the neurotransmitter acetylcholine, is synthesized in only small amounts in the brain, so the choline concentration in the brain may vary depending on the plasma concentration and the transport rate across the blood-brain barrier. To elucidate the transport mechanism of choline, we carried out uptake experiments with mouse brain capillary endothelial cells in culture (MBEC4). [3H]Choline uptake was linear for up to 5 min. An examination of the concentration dependence of [3H]choline uptake revealed the operation of both saturable (Jmax = 423+/-27 pmol min(-1) (mg protein)(-1) and Kt = 20.0+/-3.1 microM) and non-saturable (kd = 1.23+/-0.045 microL min(-1)(mgprotein)-1) processes. The saturable process was independent of Na+ and pH, but was dependent on membrane potential as a driving force. Various basic drugs and endogenous substances, including substrates and inhibitors of the organic cation transporter, significantly inhibited the [3H]choline uptake. These data suggest that choline was taken up into the endothelial cells via two routes and that a membrane potential-dependent carrier-mediated transport system may participate in choline transport across the blood-brain barrier.
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Affiliation(s)
- N Sawada
- Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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22
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Mazgalev TN, Garrigue S, Mowrey KA, Yamanouchi Y, Tchou PJ. Autonomic modification of the atrioventricular node during atrial fibrillation: role in the slowing of ventricular rate. Circulation 1999; 99:2806-14. [PMID: 10351976 DOI: 10.1161/01.cir.99.21.2806] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Postganglionic vagal stimulation (PGVS) by short bursts of subthreshold current evokes release of acetylcholine from myocardial nerve terminals. PGVS applied to the atrioventricular node (AVN) slows nodal conduction. However, little is known about the ability of PGVS to control ventricular rate (VR) during atrial fibrillation (AF). METHODS AND RESULTS To quantify the effects and establish the mechanism of PGVS on the AVN, AF was simulated by random high right atrial pacing in 11 atrial-AVN rabbit heart preparations. Microelectrode recordings of cellular action potentials (APs) were obtained from different AVN regions. Five intensities and 5 modes of PGVS delivery were evaluated. PGVS resulted in cellular hyperpolarization, along with depressed and highly heterogeneous intranodal conduction. Compact nodal AP exhibited decremental amplitude and dV/dt and multiple-hump components, and at high PGVS intensities, a high degree of concealed conduction resulted in a dramatic slowing of the VR. Progressive increase of PGVS intensity and/or rate of delivery showed a significant logarithmic correlation with a decrease in VR (P<0.001). Strong PGVS reduced the mean VR from 234 to 92 bpm (P<0.001). The PGVS effects on the cellular responses and VR during AF were fully reproduced in a model of direct acetylcholine injection into the compact AVN via micropipette. CONCLUSIONS These studies confirmed that PGVS applied during AF could produce substantial VR slowing because of acetylcholine-induced depression of conduction in the AVN.
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Affiliation(s)
- T N Mazgalev
- Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio,USA.
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23
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Hilgert M, Nöldner M, Chatterjee SS, Klein J. KA-672 inhibits rat brain acetylcholinesterase in vitro but not in vivo. Neurosci Lett 1999; 263:193-6. [PMID: 10213168 DOI: 10.1016/s0304-3940(99)00149-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
KA-672, a lipophilic benzopyranone derivative which is currently under development as a cognitive enhancer and antidementia drug, has previously been shown to have facilitatory effects on learning and memory in rats at doses of 0.1-1 mg/kg. We now report that KA-672 inhibited the activity of acetylcholinesterase (AChE), measured in vitro in rat brain cortical homogenate, with an IC50 value of 0.36 microM indicating that KA-672 may improve cognitive functions as a consequence of AChE inhibition. However, when we employed the microdialysis procedure to monitor acetylcholine (ACh) release from rat hippocampus, no effect of KA-672 (0.1-10 mg/kg) was found, indicating a lack of inhibition of brain AChE under in vivo-conditions. [14C]-labelled KA-672 was found to easily penetrate the blood-brain barrier, and an apparent concentration of 0.22 nmol/g brain (equivalent to 0.39 microM tissue concentration) was calculated following an i.p. injection of 1 mg/kg KA-672. However, no labelled substance could be detected in hippocampal microdialysates or in cerebrospinal fluid (CSF) taken from the cisterna magna, indicating that the concentration of KA-672 in brain extracellular fluid must have been below 0.01 microM. We conclude that KA-672 is a potent AChE inhibitor, an activity which, however, does not contribute to its behavioural effects in vivo because the lipophilic drug does not reach sufficient concentrations in the extracellular fluid, apparently due to cellular sequestration.
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Affiliation(s)
- M Hilgert
- Department of Pharmacology, University of Mainz, Germany
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24
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Erb C, Seidel A, Frank H, Platt KL, Oesch F, Klein J. Formation of N-methylnicotinamide in the brain from a dihydropyridine-type prodrug: effect on brain choline. Biochem Pharmacol 1999; 57:681-4. [PMID: 10037454 DOI: 10.1016/s0006-2952(98)00338-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enhancement of brain choline levels is a possible therapeutic option in neurodegenerative diseases; however, brain choline levels are held within narrow limits by homeostatic mechanisms including the rapid clearance of excess choline from the brain. The present study tests whether N-methylnicotinamide (NMN), an inhibitor of the outward transport of choline from the brain, can elevate brain choline levels in vivo. As NMN does not cross the blood-brain barrier, we synthesized and administered the brain-permeable prodrug, 1,4-dihydro-N-methyl-nicotinamide (DNMN), and tested its effect on the levels of NMN and choline in brain extracellular fluid, using the microdialysis procedure. Administration of DNMN (1 mmol/kg s.c.) caused a 4- and 9-fold increase in plasma and liver NMN levels, respectively, as determined by HPLC. Concomitantly, the brain tissue levels of NMN were increased by a factor of twenty. In brain extracellular fluid, the injection of DNMN (1-3 mmol/kg s.c.) elevated NMN levels by 3- to 10-fold to maximum levels of >10 microM. In spite of these enhanced NMN levels, the choline concentrations in the brain extracellular fluid and in the cerebrospinal fluid (4.7 microM) remained unchanged or were even slightly decreased. Microsomal incubations of DNMN indicated that cytochrome P-450 3A isoforms may be involved in NMN formation in the liver, but not in the brain. We conclude that DNMN, a brain-permeable prodrug of NMN, is efficiently oxidized to NMN in the brain, but a 10-fold increase in extracellular NMN levels is not sufficient to reduce the clearance of choline from the brain.
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Affiliation(s)
- C Erb
- Department of Pharmacology, University of Mainz, Germany
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25
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Rae C, Scott RB, Thompson CH, Dixon RM, Dumughn I, Kemp GJ, Male A, Pike M, Styles P, Radda GK. Brain biochemistry in Duchenne muscular dystrophy: a 1H magnetic resonance and neuropsychological study. J Neurol Sci 1998; 160:148-57. [PMID: 9849797 DOI: 10.1016/s0022-510x(98)00190-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle disorder associated with an intellectual deficit which is non-progressive. We obtained localised 1H magnetic resonance spectra from the left frontal lobe and left cerebellum of 15 boys with DMD (mean age 106 months+/-32) and 15 similarly aged control boys (mean age 115 months+/-31); all boys underwent a battery of neuropsychological tests. We found a significant (P<0.01) increase in the ratio of choline-containing compounds to N-acetylaspartate (Cho/NA) in the left cerebellum in boys with DMD compared with control boys. There was no change in the creatine/NA ratio and a significant increase (P=0.03) in the Cho/creatine ratio, suggesting that the change in Cho/NA ratio was due to an increase in choline-containing compounds; this increase has been previously observed in the brain of the murine model of DMD, the mdx mouse. No significant changes were observed in spectra obtained from left frontal lobe in DMD compared to controls. We also observed a significant association between Cho/NA in the left cerebellum, and the performance of DMD boys on the Matrix Analogies Test (MAT). The MAT is a test of visuo-spatial ability and non-verbal reasoning which requires neither manual dexterity nor a verbal response for an adequate performance. A comparison of DMD boys whose cerebellar Cho/NA fell within 2 standard deviations of the control norm (0.56+/-0.24) with DMD boys whose cerebellar Cho/NA was outside this range (i.e. >0.80) revealed a significant difference in ability on the MAT (P<0.05). DMD boys whose Cho/NA ratio is more than two standard deviations higher than controls perform significantly better on the MAT than DMD boys whose Cho/NA ratio is within the normal range. This finding suggests that the observed elevation in Cho/NA and Cho/creatine is not associated with intellectual deficit (as sampled by the MAT), and may represent a compensatory mechanism. The possible interpretations of these metabolic changes are discussed.
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Affiliation(s)
- C Rae
- MRC Biochemical and Clinical Magnetic Resonance Spectroscopy Unit, John Radcliffe Hospital, Headington, Oxford, UK.
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26
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Abstract
Choline is product and precursor to both acetylcholine and membrane phospholipids, and, in the brain, is ultimately provided by the circulation. The brain is protected from excess choline and choline deprivation by a refined system of homeostatic mechanisms that maintain a level of extracellular choline that, for its role as precursor, meets saturation criteria under normal conditions. The kinetic and activity profiles of choline are typical for a biosynthetic precursor.
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Affiliation(s)
- K Löffelholz
- Department of Pharmacology, University of Mainz, Germany
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27
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Mottin S, Laporte P, Jouvet M, Cespuglio R. Determination of NADH in the rat brain during sleep-wake states with an optic fibre sensor and time-resolved fluorescence procedures. Neuroscience 1997; 79:683-93. [PMID: 9219933 DOI: 10.1016/s0306-4522(96)00709-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The present paper reports a nanosecond time-resolved fluorescence derived from the cortex and the area of the periaqueductal gray including the nucleus raphe dorsalis (PAG-nRD) in unanaesthetized freely moving rats. The measurements were acquired through a single optic fibre transmitting a subnanosecond nitrogen laser pulse (337 nm, 15 Hz) and collecting the brain fluorescence occurring at 460 nm which might depend on mitochondrial NADH (reduced form of nicotinamide adenine dinucleotide). The fluorometric method was combined with polygraphic recordings, and this procedure allowed us to define, for the first time, variations of the 460 nm signal occurring throughout the sleep-wake cycle. In the PAG-nRD, the signal exhibited moderate heterogeneous variation in amplitude during slow-wave as compared to the waking state. Constant increases were observed during paradoxical sleep as compared to the waking state. For this state of sleep the magnitude of the variations depended on the optic fibre location. In the cortex and during either slow-wave sleep or paradoxical sleep, the signal presented moderate increases which were significant during paradoxical sleep. The magnitude of the redox variations observed either in the PAG-nRD or in the cortex might be ascribed to the oxidative energy balance which is related to sleep states.
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Affiliation(s)
- S Mottin
- T. S. I. Laboratory, CNRS-URA842, Jean Monnet University, St-Etienne, France
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28
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Takagi N, Miyake K, Taguchi T, Sugita N, Takagi K, Tamada H, Takeo S. Changes in cholinergic neurons and failure in learning function after microsphere embolism-induced cerebral ischemia. Brain Res Bull 1997; 43:87-92. [PMID: 9205800 DOI: 10.1016/s0361-9230(96)00350-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Central cholinergic neurons play an important role in learning and memory functions. The present study was undertaken to elucidate the pathological changes in learning function and acetylcholine metabolism of the cerebral cortex and hippocampus, following microsphere embolism in rats. Microspheres (48 microns) were injected into the right internal carotid artery of the rats. Learning function was determined using a passive avoidance task on the seventh day after the embolism. In the biochemical study, acetylcholine and choline contents, and choline acetyltransferase activity were measured in the cerebral cortex and hippocampus. Cortical acetylcholinesterase-containing fibers were quantitatively estimated in the embolized rat. Passive avoidance was impaired in the microsphere-embolized rat. Microsphere embolism decreased the acetylcholine concentration and choline acetyltransferase activity in the cerebral cortex and hippocampus. In the histochemical study, the length of cortical acetylcholinesterase-containing fibers was decreased, but cell density was unchanged in the ipsilateral hemisphere of the microsphere-embolized rat. The results suggest that microsphere embolism induces severe damage to cholinergic neurons, which may be related to the impairment of learning function in the ischemic brain.
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Affiliation(s)
- N Takagi
- Department of Pharmacology, Tokyo University of Pharmacy and Life Science, Hachioji, Japan
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29
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Babb SM, Appelmans KE, Renshaw PF, Wurtman RJ, Cohen BM. Differential effect of CDP-choline on brain cytosolic choline levels in younger and older subjects as measured by proton magnetic resonance spectroscopy. Psychopharmacology (Berl) 1996; 127:88-94. [PMID: 8888372 DOI: 10.1007/bf02805979] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Phosphatidylcholine (PtdCho), which is essential for membrane integrity and repair, is reduced in brain cell membranes with age. Evidence from both animal and in vitro studies indicates that cytidine 5' diphosphate choline (CDP-choline) can increase the synthesis of PtdCho; however, the effect of CDP-choline on brain choline metabolism has not previously been studied in human subjects. In this study, in vivo proton magnetic resonance spectroscopy (1H-MRS) was used to measure brain levels of cytosolic, choline-containing compounds before and after single oral doses of CDP-choline. Three hours after dosing, plasma choline increased similarly in younger (mean age 25 years) and older subjects (mean age 59 years). However, while the choline resonance in brain increased by 18% on average in younger subjects, it decreased by almost 6% in older subjects (P = 0.028). These results may be explained by a previously observed decrease in brain choline uptake, but not cytidine uptake, in older subjects. Additional intracellular cytidine following the administration of CDP-choline should lead to the increased incorporation of choline already present in brain into membrane PtdCho, which is not MRS-visible, consequently lowering the brain choline resonance below that of pre-treatment values. These results suggest that the cytidine moiety of CDP-choline stimulates phosphatidylcholine synthesis in human brain cell membranes in older subjects.
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Affiliation(s)
- S M Babb
- Brain Imaging Center, McLean Hospital, Belmont, MA 02178, USA
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30
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Aubert I, Cécyre D, Gauthier S, Quirion R. Comparative ontogenic profile of cholinergic markers, including nicotinic and muscarinic receptors, in the rat brain. J Comp Neurol 1996; 369:31-55. [PMID: 8723701 DOI: 10.1002/(sici)1096-9861(19960520)369:1<31::aid-cne3>3.0.co;2-l] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The ontogenic profiles of several cholinergic markers were assessed in the rat brain by using quantitative in vitro receptor autoradiography. Brain sections from animals at different stages of development were processed with [3H]AH5183 (vesamicol; vesicular acetylcholine transport sites), [3H]N-methylcarbamylcholine (alpha(4)beta(2) nicotinic receptor sites), [3H]hemicholinium-3 (high-affinity choline uptake sites), [3H]3-quinuclidinyl benzilate (total population of muscarinic receptor sites), [3H]4-DAMP (muscarinic M1/M3 receptor sites), [3H]pirenzepine (muscarinic M1 receptor sites), and [3H]AF-DX 116 and [3H]AF-DX 384 (muscarinic M2 receptor sites) as radiolabeled probes. The results revealed that, by the end of the prenatal period (embryonic day 20), the densities of nicotinic receptor and vesicular acetylcholine transport sites already represented a considerable proportion of those observed in adulthood (postnatal day 60) in different laminae of the frontal, parietal, and occipital cortices, in the layers of Ammon's horn fields and the dentate gyrus of the hippocampal formation, as well as in the amygdaloid body, the olfactory tubercle, and the striatum. In contrast, at that stage, the densities of total muscarinic, M1/M3, M1, and possibly M2 receptor and high-affinity choline uptake sites represent only a small proportion of levels seen in the adult. Differences were also observed in the postnatal ontogenic profiles of nicotinic, muscarinic, vesamicol, and high-affinity choline uptake sites. For example, between postnatal weeks 3 and 5, the levels of M1/M3 and M1 sites were at least as high as in the adult, whereas M2 and high-affinity choline uptake site densities appeared to be delayed and to reach adult values only after postnatal week 5. With regard to cholinergic innervation in the developing rat brain, the present findings suggest a temporal establishment of several components of the cholinergic systems. The first components are the vesicular acetylcholine transporter and nicotinic sites; these are followed by M1/M3 and M1 sites and, finally, by M2 and high-affinity choline uptake sites.
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Affiliation(s)
- I Aubert
- Douglas Hospital Research Centre, Verdun, Quebec, Canada
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31
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Tohgi H, Abe T, Kimura M, Saheki M, Takahashi S. Cerebrospinal fluid acetylcholine and choline in vascular dementia of Binswanger and multiple small infarct types as compared with Alzheimer-type dementia. J Neural Transm (Vienna) 1996; 103:1211-20. [PMID: 9013408 DOI: 10.1007/bf01271206] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The acetylcholine (ACh) and choline (Ch) concentrations in the cerebrospinal fluid were investigated in patients with vascular dementia of the Binswanger type (VDBT) or multiple small infarct type (MSID) as compared with patients with Alzheimer-type dementia (ATD). The ACh concentration in patients with ATD was found to be significantly lower than in controls (73%, p < 0.0001), and showed a significant positive correlation with dementia scale scores (rs = 0.63, p < 0.03). The Ch concentration in the CSF of ATD patients was approximately the same as in controls. In VDBT/MSID patients, the ACh concentration was significantly lower than in controls (p < 0.001) also showing a significant positive correlation with dementia scale scores (rs = 0.62, p < 0.02), but was significantly higher than in ATD patients (p < 0.001). Moreover, the Ch concentration in VDBT/MSID patients was significantly higher than in controls (p < 0.001) or ATD patients (p < 0.001). These results suggest that simultaneous determination of ACh and Ch concentrations in CSF may be useful for differentiating VDBT/MSID from ATD and that increasing the ACh level using cholinergic agents may be a beneficial therapeutic strategy for the treatment of ATD as well as VDBT/MSIT, and is worthy of further investigation.
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Affiliation(s)
- H Tohgi
- Department of Neurology, Iwate Medical University, Morioka, Japan
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32
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Kozuka M, Iwata N. Changes in levels of monoamines and their metabolites in incompletely ischemic brains of spontaneously hypertensive rats. Neurochem Res 1995; 20:1429-35. [PMID: 8789604 DOI: 10.1007/bf00970590] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In order to investigate changes in levels of monoamines and their related substances together with those of other neurotransmitters (acetylcholine and GABA), choline and substances related to energy metabolism (ATP, lactate and glucose) accompanying incomplete cerebral ischemia, a bilateral common carotid artery occlusion model of spontaneously hypertensive rats (SHR) was utilized. Animals were subjected to 1 or 2 h ischemia. Then the concentrations of substances were measured in the cerebral cortex, hippocampus and striatum and compared with control values. Due to the incomplete ischemia, ATP showed a moderate decrease, while lactate and choline increased remarkably, and GABA underwent a moderate increase. With regard to monoamines, both noradrenaline and serotonin levels were reduced in the cerebral cortex and hippocampus, whereas dopamine levels increased in the hippocampus. All monoamine metabolites, i.e. metabolites by monoamine oxidase (MAO), metabolites by catechol-O-methyltransferase (COMT), and metabolites by both MAO and COMT, underwent increases. The 3-methoxytyramine level in particular showed marked increases. Furthermore levels of precursor amino acids as well as 5-hydroxytryptophan rose. Acetylcholine decreased moderately only in the cerebral cortex. Among these changes, sustained increases in all the monoamine metabolites were characteristic of changes in the incompletely ischemic brain, suggesting that both COMT and MAO retain their activities in the incompletely ischemic brain.
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Affiliation(s)
- M Kozuka
- Neuroscience Research Laboratories, Sankyo Co., Ltd., Tokyo, Japan
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33
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Buyukuysal RL, Ulus IH, Aydin S, Kiran BK. 3,4-Diaminopyridine and choline increase in vivo acetylcholine release in rat striatum. Eur J Pharmacol 1995; 281:179-85. [PMID: 7589205 DOI: 10.1016/0014-2999(95)00241-c] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We investigated the effects of choline, 3,4-diaminopyridine and their combination on acetylcholine release from the corpus striatum of freely moving rats which were treated or not with atropine. Intraperitoneal administration of choline or intrastriatal administration of 3,4-diaminopyridine increased acetylcholine levels in striatal dialysates in a dose-dependent manner. When 3,4-diaminopyridine treatment was combined with choline, the observed effect was considerably greater than the sum of the increases produced by choline or 3,4-diaminopyridine alone. Administration of atropine (1 microM) in the dialysing medium was also found to be effective to stimulate striatal acetylcholine levels. 3,4-Diaminopyridine did not affect acetylcholine levels under these conditions. Whereas the choline-induced increase in acetylcholine release was significantly potentiated by atropine, co-administration of 3,4-diaminopyridine with choline failed to produce a further significant increase in the presence of atropine. These results suggest that a highly effective means for increasing acetylcholine release involves two concurrent treatments that increase neuronal choline levels and inhibition of the negative feedback modulation of acetylcholine release.
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Affiliation(s)
- R L Buyukuysal
- Uludag University, Medical School, Department of Pharmacology, Bursa, Turkey
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34
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Baker RR, Chang HY. MgATP inhibits the synthesis of 1-alkyl-2-acetyl-sn-glycero-3-phosphate by microsomal acetyltransferase of immature rabbit cerebral cortex. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1213:27-33. [PMID: 8011676 DOI: 10.1016/0005-2760(94)90218-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The activity of 1-alkyl-sn-glycero-3-phosphate (AGP) acetyltransferase was studied using microsomal fractions isolated from cerebral cortices of 15-day-old rabbits. Fraction P3A was isolated using buffered 0.32 M sucrose containing mercaptoethanol, EDTA and NaF. This fraction had specific AGP acetyltransferase activities which were 4.9-times those of microsomal fraction P3B isolated in 0.32 M sucrose alone. This P3B activity was increased 2.4-times after a preincubation in the presence of ATP, MgCl2 and a high-speed supernatant fraction from cerebral cortex. Further, the activities of both P3A and P3B were almost completely eliminated by preincubation in the presence of alkaline phosphatase. Thus an activation of the AGP acetyltransferase by phosphorylation was indicated. While there was little inhibition of the P3A AGP acetyltransferase in the presence of added ATP, the magnesium salt form of ATP (1 mM) was severely inhibitory, bringing about 86% inhibition for P3A and 91% for P3B. The inhibitory effects of MgADP and MgAMP were smaller, and MgATP was a much more effective inhibitor than MgCTP, MgGTP and MgUTP which brought about 20-38% inhibitions of P3A activity at 1 mM concentrations. The effect of MgATP may be of particular relevance to the synthesis of platelet activating factor (PAF) following a period of ischemia in brain. Falling MgATP levels during energy failure could relieve the inhibition of AGP acetyltransferase seen in healthy cells and allow the formation of 1-alkyl-2-acetyl-sn-glycero-3-phosphate, which is the first committed intermediate in the de novo pathway of PAF synthesis.
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Affiliation(s)
- R R Baker
- Department of Medicine, University of Toronto, Ontario, Canada
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35
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Marshall DL, Wurtman RJ. Effect of choline on basal and stimulated acetylcholine release: an in vivo microdialysis study using a low neostigmine concentration. Brain Res 1993; 629:269-74. [PMID: 8111630 DOI: 10.1016/0006-8993(93)91330-u] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Using in vivo microdialysis, we examined the ability of choline (Ch) chloride (120 mg/kg i.p.) to amplify basal and stimulated acetylcholine (ACh) release from rat striatum in the presence of high (10(-5) M) and low (5 x 10(-8) M) neostigmine concentration. High concentrations might suppress ACh release, and thus Ch dependence, by excessively stimulating presynaptic cholinergic receptors; alternatively, they could enhance Ch dependence by depriving the cholinergic terminals of Ch that would otherwise be formed intrasynaptically from the hydrolysis of ACh. Both basal and stimulated ACh release were found to be tetrodotoxin (TTX) sensitive. The concentration of neostigmine in the microdialysis fluid positively affected basal ACh levels, but had no effect on Ch levels. Ch administration significantly increased ACh release (to 136% of basal values; P < 0.01) in the presence of the low neostigmine concentration, but failed to significantly increase ACh release following local electrical depolarization of striatal neurons. In contrast, Ch failed to affect basal ACh release in the presence of the high neostigmine concentration, but did increase electrically evoked release to 408% of basal values, as compared with 250% in rats receiving saline instead of the Ch (P < 0.05). Ch administration significantly increased microdialysate Ch levels in the presence of both of the neostigmine concentrations. Local administration of oxotremorine, a muscarinic agonist, to animals receiving the lower neostigmine concentration reduced basal ACh release and reduced the increase in basal release produced by Ch administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D L Marshall
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139
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36
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Rylett RJ, Goddard S, Lambros A. Regulation of expression of cholinergic neuronal phenotypic markers in neuroblastoma LA-N-2. J Neurochem 1993; 61:1388-97. [PMID: 8376993 DOI: 10.1111/j.1471-4159.1993.tb13632.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cholinergic neurons in PNS and CNS are identified by the presence of choline acetyltransferase and the accumulation of choline by a high-affinity, sodium-coupled choline transporter to be used for acetylcholine synthesis. It appears that expression of choline acetyltransferase can be altered by several physiological conditions, including hormones and trophic factors, but little is known about control of expression of the sodium-coupled choline carrier or whether these two phenotypic markers are regulated similarly. In the present study, the cholinergic human neuroblastoma LA-N-2 was used to investigate regulation of expression of choline acetyltransferase and choline uptake activity associated with differentiation and neurite extension. Cells grown in serum-containing basal medium maintained a relatively undifferentiated morphology, expressed low levels of choline acetyltransferase activity, and accumulated choline by a sodium-dependent process followed by conversion to acetylcholine. Transfer of cells to an enriched, serum-free defined medium resulted in morphological and neurochemical differentiation, with an enhancement of cholinergic phenotype. Hemicholinium-sensitive choline uptake activity was increased about sixfold over a 4-day period, with no change in choline acetyltransferase or acetylcholinesterase specific activity. Acetylcholine synthesis was increased in parallel with the changes in choline accumulation; choline metabolism in the differentiated cells differed significantly from that observed in the undifferentiated cells, with proportionally less converted to phosphorylcholine and proportionally more remaining as unmetabolized choline and converted to acetylcholine. The enhanced choline accumulation appeared to be mediated by an increased number of choline carriers, demonstrated by increased binding of the affinity ligand [3H]-choline mustard to the transporter and by an increased Vmax for the uptake process. The increased expression of the transport function appeared to be under transcriptional control, as the enhancement of uptake was blocked by the RNA polymerase II inhibitor alpha-amanitin as well as by the protein synthesis inhibitor cycloheximide. These results show that expression of sodium-coupled choline carriers and choline acetyltransferase may be regulated separately in the differentiating neuroblastoma LA-N-2 and that neurotransmitter synthesis is controlled by provision of precursor rather than at the level of the biosynthetic enzyme.
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Affiliation(s)
- R J Rylett
- Department of Physiology, University of Western Ontario, London, Canada
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Bertrand N, Ishii H, Beley A, Spatz M. Biphasic striatal acetylcholine release during and after transient cerebral ischemia in gerbils. J Cereb Blood Flow Metab 1993; 13:789-95. [PMID: 8360285 DOI: 10.1038/jcbfm.1993.100] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Acetylcholine (ACh) release into the extracellular space was measured by HPLC with electrochemical detection after in vivo intracerebral microdialysis in the striatum of gerbils subjected to 15 min of bilateral carotid artery occlusion followed by 5 h of recirculation. Tissue ACh and choline (Ch) contents were also determined during ischemia and after 5, 30, 60, and 120 min of reflow. Fifteen minutes of ischemia led to a significant transient increase in extracellular ACh concentration (threefold after 7.5 min of ischemia) concomitant with a reduced endogenous ACh level (-62%) and increased tissue Ch content (ninefold). Recirculation significantly reduced the ACh release during the early period of reflow (-50% vs. basal level), followed by a significant increase in ACh release between 1 and 3 h of reflow (45-55% vs. basal level) and subsequent normalization. Simultaneously, a "rebound" of tissue ACh level occurred in the early period of reflow (fourfold vs. ischemic value), followed by gradual normalization after 2 h of reperfusion, whereas a rapid decrease in tissue Ch levels was found after 30 min of reflow. These findings represent the first demonstration of a biphasic release of ACh during ischemia and reperfusion, as assessed by intracerebral microdialysis in gerbils.
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Affiliation(s)
- N Bertrand
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
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38
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Komabayashi T, Noguchi M, Izawa T, Suda K, Tsuboi M. Mechanism of isoprenaline-stimulated diacylglycerol formation in rat parotid acinar cells. JAPANESE JOURNAL OF PHARMACOLOGY 1993; 62:379-85. [PMID: 8230865 DOI: 10.1254/jjp.62.379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The kinetics and mechanism of sn-1,2-diacylglycerol (DAG) formation induced by isoprenaline were studied in rat parotid acinar cells. DAG accumulation induced by 100 microM isoprenaline reached its maximum at 1 min, rapidly decreased (about 50%) at 5 min and then remained constant for 30 min. DAG accumulation 1 min after isoprenaline treatment was dose-dependent. Either propranolol or phentolamine inhibited isoprenaline-stimulated DAG accumulation in a dose-dependent manner. Addition of a vasoactive intestinal polypeptide, forskolin, or dibutyryl cyclic AMP had no effect on DAG accumulation. Isoprenaline did not cause the release of [3H]choline or [3H]ethanolamine metabolites into the medium. Based on the kinetics of DAG formation and [32P]phosphoinositide breakdown, we conclude that isoprenaline-induced DAG formation was mainly related to the hydrolysis of [32P]phosphatidylinositol 4,5-bisphosphate ([32P]PIP2). These results suggest that the effect of isoprenaline on DAG formation is mediated by alpha 1-adrenoceptor activation, that it is not related to the increase in cyclic AMP, and that it is closely related to PIP2 hydrolysis.
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Affiliation(s)
- T Komabayashi
- Department of Physiology and Pharmacology, Tokyo College of Pharmacy, Japan
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Andriamampandry C, Kanfer JN. Inhibition of cytosolic human forebrain choline acetyltransferase activity by phospho-L-serine: a phosphomonoester that accumulates during early stages of Alzheimer's disease. Neurobiol Aging 1993; 14:367-72. [PMID: 8367018 DOI: 10.1016/0197-4580(93)90123-s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
There is no satisfactory explanation for the cholinergic deficit characteristic of Alzheimer's disease. We have performed a series of experiments which demonstrate that (a) an inhibitor of cytosolic human brain choline acetyltransferase is present in the cytosol of Alzheimer brain tissue, (b) human brain cytosolic choline acetyltransferase activity is inhibited by phospho-L-serine in a competitive manner. Cytosol was prepared from human forebrain or amygdala and the Km for choline and acetyl CoA of the choline acetyltransferase were 750 microM and 12.5 microM, respectively. Phospho-L-serine was found to be a competitive inhibitor of this enzyme with respect to choline but not with respect to acetyl CoA with a Ki of 750 microM for the human forebrain and 3 mM for human amygdala. These concentrations of phospho-L-serine are present in brain tissue at early stages of Alzheimer's disease. Several other phosphomonoesters and phosphodiesters that are increased in Alzheimer's disease were either less inhibitory or without effect. The addition of heat denatured and non-heat denatured cytosol from Alzheimers forebrain inhibited the choline acetyltransferase activity present in control human brain cytosol. The inhibitory activity of the Alzheimers cytosol was retained in TCA deproteinized samples and removed by dialysis or by alkaline phosphatase treatment. Dialysis of the cytosol increased the choline acetyltransferase activity of 5 of 8 Alzheimer's disease samples from 21 to 118% with p values of < 0.025 or < 0.001, respectively. These observations provide evidence that an endogenous non-proteinaceous, dialyzable, phosphomonoester, present in Alzheimers brain inhibits the choline acetyltransferase of both control and Alzheimers brain.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Andriamampandry
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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40
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Tsujimoto S, Sakaki T, Morimoto T, Tominaga M. The effect of acetylcholinesterase inhibitor (SDZ ENA 713) for r-CBF and focal cerebral ischaemia. Acta Neurochir (Wien) 1993; 124:127-31. [PMID: 8304058 DOI: 10.1007/bf01401134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of the present study was to examine the effect of Acetylcholinesterase inhibitor (AChEI) on r-CBF (group A) and its protecting effect on focal ischaemic cell damage (group B). The pial arterial diameter and the r-CBF were measured with a width analyzer and with a laser Doppler flowmeter through a cat cranial window on the ectosylvian gyrus. The ischaemic area was measured histologically. We used intravenous injection of AChEI([-])(S)-N-ethyl-3-[(1-dimethyl- amino)ethyl]-N-methyl-phenylcarbamate, SDZENA 713, Sands Pharmacy) to block AChE. Twenty minutes after injection AChEI (0.6 mg/kg) the pial arteriole dilated 108.5 +/- 1.8% and the r-CBF increased 115.4 +/- 2.6%. The pial arteriole dilated maximally to 137.6 +/- 6.5% at 120 minutes after injection and the r-CBF increased maximally to 137.1 +/- 19.5% at 60 minutes after injection. The protecting effect was evaluated using cats and 1 hour of occlusion of the middle cerebral artery (MCA). Twenty minutes after injection of AChEI, the pial arteriole dilated to 116.7 +/- 2.4% and the r-CBF increased to 111.9 +/- 2.6% significantly. During MCA occlusion the r-CBF decreased to 24.7-41.4% in group B and 25.1-32.6% in sham group (group C). The pial arteriole dilated 145.0-184.0% in group C and 150.7-171.6% in group B during MCA occlusion and 30 minutes after reperfusion the pial arteriole returned to 120.0 +/- 3.3% in group C and 123.4 +/- 11.3% in group B. There were no significant changes in the r-CBF and the vessel diameter between group B and C during the 2 hours after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Tsujimoto
- Department of Neurosurgery, Nara Medical University, Japan
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41
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Dunbar GL, Rylett RJ, Schmidt BM, Sinclair RC, Williams LR. Hippocampal choline acetyltransferase activity correlates with spatial learning in aged rats. Brain Res 1993; 604:266-72. [PMID: 8457854 DOI: 10.1016/0006-8993(93)90378-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Age-related cognitive deficits in both humans and experimental animals appear to relate to dysfunction of basal forebrain cholinergic neuron systems. The present study assessed spatial learning performance in a water maze task as a function of choline acetyltransferase and high-affinity choline uptake specific activity (the two phenotypic markers for cholinergic neurons) in frontal cortex, hippocampus and striatum of aged male Fischer-344 rats. We observed that increased hippocampal choline acetyltransferase activity was related to better performance on the water maze task, and that, of the individual measures, hippocampal choline acetyltransferase activity was the best predictor of behavioral performance in the spatial learning task.
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Affiliation(s)
- G L Dunbar
- Department of Psychology, Central Michigan University, Mt. Pleasant 48859
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42
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Scremin OU, Jenden DJ. Acetylcholine turnover and release: the influence of energy metabolism and systemic choline availability. PROGRESS IN BRAIN RESEARCH 1993; 98:191-5. [PMID: 8248508 DOI: 10.1016/s0079-6123(08)62398-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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43
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Parsons SM, Prior C, Marshall IG. Acetylcholine transport, storage, and release. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1993; 35:279-390. [PMID: 8463062 DOI: 10.1016/s0074-7742(08)60572-3] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
ACh is released from cholinergic nerve terminals under both resting and stimulated conditions. Stimulated release is mediated by exocytosis of synaptic vesicle contents. The structure and function of cholinergic vesicles are becoming known. The concentration of ACh in vesicles is about 100-fold greater than the concentration in the cytoplasm. The AChT exhibits the lowest binding specificity among known ACh-binding proteins. It is driven by efflux of protons pumped into the vesicle by the V-type ATPase. A potent pharmacology of the AChT based on the allosteric VR has been developed. It has promise for clinical applications that include in vivo evaluation of the density of cholinergic innervation in organs based on PET and SPECT. The microscopic kinetics model that has been developed and the very low transport specificity of the vesicular AChT-VR suggest that the transporter has a channel-like or multidrug resistance protein-like structure. The AChT-VR has been shown to be tightly associated with proteoglycan, which is an unexpected macromolecular relationship. Vesamicol and its analogs block evoked release of ACh from cholinergic nerve terminals after a lag period that depends on the rate of release. Recycling quanta of ACh that are sensitive to vesamicol have been identified electrophysiologically, and they constitute a functional correlate of the biochemically identified VP2 synaptic vesicles. The concept of transmitter mobilization, including the observation that the most recently synthesized ACh is the first to be released, has been greatly clarified because of the availability of vesamicol. Differences among different cholinergic nerve terminal types in the sensitivity to vesamicol, the relative amounts of readily and less releasable ACh, and other aspects of the intracellular metabolism of ACh probably are more apparent than real. They easily could arise from differences in the relative rates of competing or sequential steps in the complicated intraterminal metabolism of ACh rather than from fundamental differences among the terminals. Nonquantal release of ACh from motor nerve terminals arises at least in part from the movement of cytoplasmic ACh through the AChT located in the cytoplasmic membrane, and it is blocked by vesamicol. Possibly, the proteoglycan component of the AChT-VR produces long-term residence of the macromolecular complex in the cytoplasmic membrane through interaction with the synaptic matrix. The preponderance of evidence suggests that a significant fraction of what previously, heretofore, had been considered to be nonquantal release from the motor neuron actually is quantal release from the neuron at sites not detected electrophysiologically.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- S M Parsons
- Department of Chemistry, University of California, Santa Barbara 93106
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44
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Tucek S. Short-term control of the synthesis of acetylcholine. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1993; 60:59-69. [PMID: 8480028 DOI: 10.1016/0079-6107(93)90013-a] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S Tucek
- Institute of Physiology, Czechoslovak Academy of Sciences, Prague
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45
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Rylett RJ, Schmidt BM. Regulation of the synthesis of acetylcholine. PROGRESS IN BRAIN RESEARCH 1993; 98:161-6. [PMID: 8248504 DOI: 10.1016/s0079-6123(08)62394-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- R J Rylett
- Department of Physiology, University of Western Ontario, London, Canada
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46
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Andriamampandry C, Massarelli R, Kanfer JN. Properties of a partially purified phosphodimethylethanolamine methyltransferase from rat brain cytosol. Biochem J 1992; 288 ( Pt 1):267-72. [PMID: 1445270 PMCID: PMC1132108 DOI: 10.1042/bj2880267] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The presence of cytosolic S-adenosylmethionine-dependent N-methyltransferase(s) activity(ies) capable of converting phosphoethanolamine into phosphocholine has been recently demonstrated in the rat brain. At least two enzymes are involved in the methylation of phosphoethanolamine to phosphocholine and these are separable by ammonium sulphate fractionation. The enzyme catalysing the last step of this methylation process is present in the 50-80% ammonium sulphate fraction. A 220-fold purified enzyme has been obtained with sequentially employed Q-Sepharose fast flow and octyl-Sepharose CL4B column chromatography. The maximum enzyme activity was at pH 9.5. The Km values for S-adenosylmethionine, the methyl donor, and phosphodimethylethanolamine, the methyl acceptor, were 125 microM and 750 microM respectively. This phosphodimethylethanolamine N-methyltransferase was found to be calcium-dependent, with a 4-fold increase in activity at 0.5 mM-CaCl2. S-Adenosylhomocysteine at 0.5 mM caused 100% inhibition of the activity. The effects of various structural analogues on the phosphodimethylethanolamine N-methyltransferase activity were also investigated and these results suggest that the enzyme is specific to the substrate. These results provide evidence for the existence of the pathway for the methylation of phosphoethanolamine to phosphocholine in rat brain cytosol.
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Affiliation(s)
- C Andriamampandry
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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Yanai J, Avraham Y, Levy S, Maslaton J, Pick CG, Rogel-Fuchs Y, Zahalka EA. Alterations in septohippocampal cholinergic innervations and related behaviors after early exposure to heroin and phencyclidine. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1992; 69:207-14. [PMID: 1424097 DOI: 10.1016/0165-3806(92)90161-o] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mice were exposed to diacetylmorphine (heroin) or phencyclidine (PCP) prenatally or neonatally. At a later age, they were tested for hippocampus-related behavioral deficits and concomitant alterations in the septohippocampal cholinergic innervations. Actually, this is an application of the previously established phenobarbital neuroteratogenicity model to heroin and PCP. Prenatal exposure was accomplished transplacentally by injecting the mother 10 mg/kg heroin or PCP on gestation days 9-18. Neonatal administrations were applied directly by injections of 10 mg/kg of either drug to the pups between neonatal days 2-21. At the age of 50 days, mice exposed to heroin and PCP prenatally exhibited a 107% and 159% increase in their muscarinic cholinergic receptors Bmax, respectively. Neonatal exposure to heroin or PCP caused an 83% and 76% increase in the receptors respectively. On the behavioral level, both prenatal and neonatal exposure to heroin or PCP reduced performance in the hippocampus related eight-arm maze and Morris mazes. Depending on the drug, the test and the period of drug administration, the reduction ranged between 10% and 75%. The results suggest that heroin and PCP induce alterations in the septohippocampal cholinergic innervations and in related behavioral performance. Further studies are necessary in order to connect the biochemical and behavioral events in causal relationships.
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Affiliation(s)
- J Yanai
- Melvin A. and Eleanor Ross Laboratory for Studies in Neural Birth Defects, Department of Anatomy and Embryology, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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48
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Abstract
In physiological conditions, there is a net transport of choline from brain to blood, despite the fact that the choline concentration is higher in plasma than in CSF. Because of the blood-brain barrier characteristics, such passage against the concentration gradient takes place necessarily through endothelial cells. To get a better understanding of this phenomenon, [3H]choline uptake properties have been analyzed in capillaries isolated from bovine brain. [3H]Choline uptake was linear with time for up to 1 h. Nonlinear regression analysis of the uptake rates at different substrate concentrations gave the best fit to a system of two components, one of which was saturable (Km = 17.8 +/- 4.8 microM; Vmax = 11.3 +/- 3.4 pmol/min/mg of protein) and the other of which was nonsaturable at concentrations up to 200 microM. The [3H]choline transport was significantly reduced in the absence of sodium and after incubation with 10(-4) M ouabain for 30 min. Ouabain also inhibited choline uptake in purified cerebral endothelial cells, but not in the endothelium isolated from bovine aorta. Accordingly, cerebral endothelial cells were able to concentrate [3H]choline, with this effect being abolished by ouabain, whereas in aortic endothelial cells the [3H]choline intracellular concentration was never higher than that of the incubation medium. These results suggest that the blood-brain barrier endothelium is specifically provided with an energy-dependent choline transport system, which may explain the choline efflux from the brain and the maintenance of a low choline concentration in the cerebral extracellular space.
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Affiliation(s)
- E Galea
- Department of Physiology, School of Medicine, Universidad Autónoma de Madrid, Spain
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49
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Abstract
Cerebral blood flow (CBF) and the arteriovenous (A-V) difference for choline (Ch) across brain, lung, splanchnic territory, liver, kidney, and lower limb were studied in anesthetized, mechanically ventilated rats subjected to 10-20-min periods of hypoxia induced by lowering the inspired O2 concentration to 13%. A large, time-dependent increase in arterial blood Ch concentration occurred during hypoxia. This phenomenon coincided with a net rate of uptake of Ch by the brain during hypoxia (0.81 +/- 0.24 nmol/min, n = 10; p less than 0.05), which contrasted with a net rate of loss of Ch by this organ during the control period that preceded hypoxia (-0.20 +/- 0.08 nmol/min, n = 10; p less than 0.05). During hypoxia, lungs and splanchnic territory showed negative A-V differences for Ch levels (net Ch loss), whereas brain, liver, kidney, and lower limb showed positive A-V differences for Ch levels (net Ch uptake). Ch output from lungs was already detected at 5 min within the period of hypoxia and reversed rapidly after restoration of normal oxygenation. On the other hand, Ch output from the splanchnic territory became evident only 10 min after commencement of hypoxia and outlasted this experimental condition. It is concluded that extracerebral production of Ch during hypocapnic hypoxia raises the arterial concentration of this molecule and, by reversing the gradient across cerebral capillaries, prevents the cerebral loss of Ch in this condition.
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Affiliation(s)
- O U Scremin
- West L.A. V.A.M.C. Research Service (Wadsworth Division), California 90073
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50
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Rícný J, Tucek S, Nováková J. Acetylcarnitine, carnitine and glucose diminish the effect of muscarinic antagonist quinuclidinyl benzilate on striatal acetylcholine content. Brain Res 1992; 576:215-9. [PMID: 1515917 DOI: 10.1016/0006-8993(92)90683-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The content of acetylcholine (ACh) in the striatum, brain cortex and hippocampus of rats was lowered 20-180 min after intraperitoneal injection of the muscarinic antagonist quinuclidinyl benzilate (QNB). The depletion of ACh content in the striatum was diminished in animals treated with a single dose of acetyl-L-carnitine, L- or D,L-carnitine, or D-glucose. It is likely that QNB stimulates ACh release by blocking presynaptic muscarinic autoreceptors and that acetylcarnitine, carnitine and glucose support the resynthesis of ACh by increasing the availability of acetylcoenzyme A. They do not have the same consistent effect in the brain cortex and hippocampus; this difference may be related to the lower turnover rate of ACh and to the difference in the anatomical arrangement of cholinergic structures in these parts of the brain.
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Affiliation(s)
- J Rícný
- Institute of Physiology, Czechoslovak Academy of Sciences, Prague
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