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Tortosa V, Pietropaolo V, Brandi V, Macari G, Pasquadibisceglie A, Polticelli F. Computational Methods for the Identification of Molecular Targets of Toxic Food Additives. Butylated Hydroxytoluene as a Case Study. Molecules 2020; 25:E2229. [PMID: 32397407 PMCID: PMC7248939 DOI: 10.3390/molecules25092229] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 11/24/2022] Open
Abstract
Butylated hydroxytoluene (BHT) is one of the most commonly used synthetic antioxidants in food, cosmetic, pharmaceutical and petrochemical products. BHT is considered safe for human health; however, its widespread use together with the potential toxicological effects have increased consumers concern about the use of this synthetic food additive. In addition, the estimated daily intake of BHT has been demonstrated to exceed the recommended acceptable threshold. In the present work, using BHT as a case study, the usefulness of computational techniques, such as reverse screening and molecular docking, in identifying protein-ligand interactions of food additives at the bases of their toxicological effects has been probed. The computational methods here employed have been useful for the identification of several potential unknown targets of BHT, suggesting a possible explanation for its toxic effects. In silico analyses can be employed to identify new macromolecular targets of synthetic food additives and to explore their functional mechanisms or side effects. Noteworthy, this could be important for the cases in which there is an evident lack of experimental studies, as is the case for BHT.
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Affiliation(s)
- Valentina Tortosa
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
| | - Valentina Pietropaolo
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
| | - Valentina Brandi
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
| | - Gabriele Macari
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
| | - Andrea Pasquadibisceglie
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, 00146 Rome, Italy; (V.T.); (V.P.); (V.B.); (G.M.); (A.P.)
- National Institute of Nuclear Physics, Roma Tre University, 00146 Rome, Italy
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Hondebrink L, Zwartsen A, Westerink RHS. Effect fingerprinting of new psychoactive substances (NPS): What can we learn from in vitro data? Pharmacol Ther 2017; 182:193-224. [PMID: 29097307 DOI: 10.1016/j.pharmthera.2017.10.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The use of new psychoactive substances (NPS) is increasing and currently >600 NPS have been reported. However, limited information on neuropharmacological and toxicological effects of NPS is available, hampering risk characterization. We reviewed the literature on the in vitro neuronal modes of action to obtain effect fingerprints of different classes of illicit drugs and NPS. The most frequently reported NPS were selected for review: cathinones (MDPV, α-PVP, mephedrone, 4-MEC, pentedrone, methylone), cannabinoids (JWH-018), (hallucinogenic) phenethylamines (4-fluoroamphetamine, benzofurans (5-APB, 6-APB), 2C-B, NBOMes (25B-NBOMe, 25C-NBOMe, 25I-NBOMe)), arylcyclohexylamines (methoxetamine) and piperazine derivatives (mCPP, TFMPP, BZP). Our effect fingerprints highlight the main modes of action for the different NPS studied, including inhibition and/or reversal of monoamine reuptake transporters (cathinones and non-hallucinogenic phenethylamines), activation of 5-HT2receptors (hallucinogenic phenethylamines and piperazines), activation of cannabinoid receptors (cannabinoids) and inhibition of NDMA receptors (arylcyclohexylamines). Importantly, we identified additional targets by relating reported effect concentrations to the estimated human brain concentrations during recreational use. These additional targets include dopamine receptors, α- and β-adrenergic receptors, GABAAreceptors and acetylcholine receptors, which may all contribute to the observed clinical symptoms following exposure. Additional data is needed as the number of NPS continues to increase. Also, the effect fingerprints we have obtained are still incomplete and suffer from a large variation in the reported effects and effect sizes. Dedicated in vitro screening batteries will aid in complementing specific effect fingerprints of NPS. These fingerprints can be implemented in the risk assessments of NPS that are necessary for eventual control measures to reduce Public Health risks.
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Affiliation(s)
- Laura Hondebrink
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht University, The Netherlands
| | - Anne Zwartsen
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht University, The Netherlands; Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands.
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Yang H, Wang Y, Zhang Y, Zhang Y, Xu MS, Yuan J, Yu T. Astrocytes contribute to the effects of etomidate on synaptic transmission in rat primary somatosensory cortex. Brain Res 2016; 1642:238-243. [PMID: 27045115 DOI: 10.1016/j.brainres.2016.03.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 03/26/2016] [Accepted: 03/31/2016] [Indexed: 11/27/2022]
Abstract
Little is known about the mechanisms of unconsciousness induced by general anesthetics. Previous studies have shown that the primary somatosensory cortex (S1) is a sensitive region to a variety of intravenous general anesthetics. Etomidate is a widely used intravenous anesthetic that can influence synaptic transmission. Recently, there are some evidences suggesting that astrocytes, a type of glia cell, also contribute to information transmission in the brain, and modulate synaptic function by releasing neuroactive substances. However, it is unknown whether astrocytes influence the effects of etomidate on information transmission in S1 pyramidal neurons. In the present study, the role of astrocytes in etomidate-induced unconsciousness was investigated by using the whole-cell patch clamp technique. We observed etomidate at clinically relevant concentrations inhibited the spontaneous postsynaptic currents (sPSCs) of rat S1 pyramidal neurons in a concentration-dependent manner, and the EC50 value of etomidate for inhibiting sPSCs from the concentration-effect curve was 6.9μM. Furthermore, in the presence of fluorocitrate, a glia-selective metabolism inhibitor that blocks the aconitase enzyme, both the amplitude and frequency of sPSCs in rat S1 pyramidal neurons were reduced, and the inhibitory effects of etomidate on sPSCs amplitude was strengthened without affecting the effects of etomidate on frequency. From these data, we deduce that etomidate suppresses synaptic activity via presynaptic and postsynaptic components. Furthermore, astrocytes participate in synaptic transmission and influence the effects of etomidate on postsynaptic receptors. This study provides new insight into the role of astrocytes in etomidate-induced unconsciousness.
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Affiliation(s)
- Hao Yang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - Yuan Wang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China; Department of Anesthesiology, Affiliated Hospital of Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - Yu Zhang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China; Department of Anesthesiology, Affiliated Hospital of Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - You Zhang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - Mao-Sheng Xu
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - Jie Yuan
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China
| | - Tian Yu
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China; Department of Anesthesiology, Affiliated Hospital of Zunyi Medical College, Dalian Road, 563003 Zunyi, Guizhou, China.
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Flyktman A, Mänttäri S, Nissilä J, Timonen M, Saarela S. Transcranial light affects plasma monoamine levels and expression of brain encephalopsin in the mouse. ACTA ACUST UNITED AC 2015; 218:1521-6. [PMID: 25805701 DOI: 10.1242/jeb.111864] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 03/09/2015] [Indexed: 11/20/2022]
Abstract
Encephalopsin (OPN3) belongs to the light-sensitive transmembrane receptor family mainly expressed in the brain and retina. It is believed that light affects mammalian circadian rhythmicity only through the retinohypothalamic tract, which transmits light information to the suprachiasmatic nucleus in the hypothalamus. However, it has been shown that light penetrates the skull. Here, we present the effect of transcranial light treatment on OPN3 expression and monoamine concentrations in mouse brain and other tissues. Mice were randomly assigned to control group, morning-light group and evening-light group, and animals were illuminated transcranially five times a week for 8 min for a total of 4 weeks. The concentrations of OPN3 and monoamines were analysed using western blotting and HPLC, respectively. We report that transcranial light treatment affects OPN3 expression in different brain areas and plasma/adrenal gland monoamine concentrations. In addition, when light was administered at a different time of the day, the response varied in different tissues. These results provide new information on the effects of light on transmitters mediating mammalian rhythmicity.
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Affiliation(s)
- Antti Flyktman
- University of Oulu, Department of Biology, P.O. Box 3000, Oulu FIN-90014, Finland
| | - Satu Mänttäri
- Finnish Institute of Occupational Health, Aapistie 1, Oulu FI-90220, Finland
| | - Juuso Nissilä
- University of Oulu, Department of Biology, P.O. Box 3000, Oulu FIN-90014, Finland University of Oulu, Institute of Health Sciences, P.O. Box 5000, Oulu FIN-90014, Finland
| | - Markku Timonen
- University of Oulu, Institute of Health Sciences, P.O. Box 5000, Oulu FIN-90014, Finland
| | - Seppo Saarela
- University of Oulu, Department of Biology, P.O. Box 3000, Oulu FIN-90014, Finland
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The effects of volatile anesthetics on the extracellular accumulation of [(3)H]GABA in rat brain cortical slices. Cell Mol Neurobiol 2013; 34:71-81. [PMID: 24081560 DOI: 10.1007/s10571-013-9988-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 09/14/2013] [Indexed: 12/13/2022]
Abstract
GABA is an inhibitory neurotransmitter that appears to be associated with the action of volatile anesthetics. These anesthetics potentiate GABA-induced postsynaptic currents by synaptic GABAA receptors, although recent evidence suggests that these agents also significantly affect extrasynaptic GABA receptors. However, the effect of volatile anesthetics on the extracellular concentration of GABA in the central nervous system has not been fully established. In the present study, rat brain cortical slices loaded with [(3)H]GABA were used to investigate the effect of halothane and sevoflurane on the extracellular accumulation of this neurotransmitter. The accumulation of [(3)H]GABA was significantly increased by sevoflurane (0.058, 0.11, 0.23, 0.46, and 0.93 mM) and halothane (0.006, 0.012, 0.024, 0.048, 0072, and 0.096 mM) with an EC50 of 0.26 mM and 35 μM, respectively. TTX (blocker of voltage-dependent Na(+) channels), EGTA (an extracellular Ca(2+) chelator) and BAPTA-AM (an intracellular Ca(2+) chelator) did not interfere with the accumulation of [(3)H]GABA induced by 0.23 mM sevoflurane and 0.048 mM halothane. SKF 89976A, a GABA transporter type 1 (GAT-1) inhibitor, reduced the sevoflurane- and halothane-induced increase in the accumulation of GABA by 57 and 63 %, respectively. Incubation of brain cortical slices at low temperature (17 °C), a condition that inhibits GAT function and reduces GABA release through reverse transport, reduced the sevoflurane- and halothane-induced increase in the accumulation of [(3)H]GABA by 82 and 75 %, respectively, relative to that at normal temperature (37 °C). Ouabain, a Na(+)/K(+) ATPase pump inhibitor, which is known to induce GABA release through reverse transport, abolished the sevoflurane and halothane effects on the accumulation of [(3)H]GABA. The effect of sevoflurane and halothane did not involve glial transporters because β-alanine, a blocker of GAT-2 and GAT-3, did not inhibit the effect of the anesthetics. In conclusion, the present study suggests that sevoflurane and halothane increase the accumulation of GABA by inducing the reverse transport of this neurotransmitter. Therefore, volatile anesthetics could interfere with neuronal excitability by increasing the action of GABA on synaptic and extrasynaptic GABA receptors.
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Westphalen RI, Desai KM, Hemmings HC. Presynaptic inhibition of the release of multiple major central nervous system neurotransmitter types by the inhaled anaesthetic isoflurane. Br J Anaesth 2012; 110:592-9. [PMID: 23213036 DOI: 10.1093/bja/aes448] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Presynaptic effects of general anaesthetics are not well characterized. We tested the hypothesis that isoflurane exhibits transmitter-specific effects on neurotransmitter release from neurochemically and functionally distinct isolated mammalian nerve terminals. METHODS Nerve terminals from adult male rat brain were prelabelled with [(3)H]glutamate and [(14)C]GABA (cerebral cortex), [(3)H]norepinephrine (hippocampus), [(14)C]dopamine (striatum), or [(3)H]choline (precursor of [(3)H]acetylcholine; striatum). Release evoked by depolarizing pulses of 4-aminopyridine (4AP) or elevated KCl was quantified using a closed superfusion system. RESULTS Isoflurane at clinical concentrations (<0.7 mM; ~2 times median anaesthetic concentration) inhibited Na(+) channel-dependent 4AP-evoked release of the five neurotransmitters tested in a concentration-dependent manner. Isoflurane was a more potent inhibitor [expressed as IC(50) (SEM)] of glutamate release [0.37 (0.03) mM; P<0.05] compared with the release of GABA [0.52 (0.03) mM], norepinephrine [0.48 (0.03) mM], dopamine [0.48 (0.03) mM], or acetylcholine [0.49 (0.02) mM]. Inhibition of Na(+) channel-independent release evoked by elevated K(+) was not significant at clinical concentrations of isoflurane, with the exception of dopamine release [IC(50)=0.59 (0.03) mM]. CONCLUSIONS Isoflurane inhibited the release of the major central nervous system neurotransmitters with selectivity for glutamate release, consistent with both widespread inhibition and nerve terminal-specific presynaptic effects. Glutamate release was most sensitive to inhibition compared with GABA, acetylcholine, dopamine, and norepinephrine release due to presynaptic specializations in ion channel expression, regulation, and/or coupling to exocytosis. Reductions in neurotransmitter release by volatile anaesthetics could contribute to altered synaptic transmission, leading to therapeutic and toxic effects involving all major neurotransmitter systems.
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Affiliation(s)
- R I Westphalen
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
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Zarantonello P, Bettini E, Paio A, Simoncelli C, Terreni S, Cardullo F. Novel analogues of ketamine and phencyclidine as NMDA receptor antagonists. Bioorg Med Chem Lett 2011; 21:2059-63. [DOI: 10.1016/j.bmcl.2011.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/02/2011] [Accepted: 02/02/2011] [Indexed: 11/15/2022]
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Abstract
BACKGROUND The Segawa syndrome is an autosomal dominant form of guanosine triphosphate cyclohydrolase deficiency, resulting in decreased dopamine and serotonin levels, typically presenting as a dopa-responsive dystonia. METHOD Case presentation of a 56-year-old man with dopa-responsive dystonia, treated with electroconvulsive therapy for a psychotic depression. RESULTS Scores on the Inventory of Depressive Symptomatology dropped from 35 before treatment to 3 after the eighth treatment session. Etomidate and succinylcholine were used as anesthetics. Apart from 2 sessions with postictal agitation, the course of electroconvulsive therapy was finished uneventfully. Electroconvulsive therapy and anesthesia had no untoward effects on motor function. CONCLUSIONS Electroconvulsive therapy can be administered safely and effectively in a patient with dopa-responsive dystonia (Segawa syndrome).
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Siegal N, Dow-Edwards D. Isoflurane anesthesia interferes with the expression of cocaine-induced sensitization in female rats. Neurosci Lett 2009; 464:52-6. [PMID: 19660521 PMCID: PMC4209471 DOI: 10.1016/j.neulet.2009.07.088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 07/15/2009] [Accepted: 07/30/2009] [Indexed: 10/20/2022]
Abstract
Repeated cocaine administration results in a progressive sensitization of behavior which typically occurs more readily in female rats than in males. Our recent studies of rats undergoing surgical procedures revealed that following anesthesia, females sensitized less than males receiving identical repeated cocaine injections. Since isoflurane acts primarily by increasing the effects of the inhibitory neurotransmitter gamma-amino butyric acid (GABA) and reducing the effects of the excitatory amino acid glutamate, these amino acids may play more prominent roles in sensitization to cocaine in females than previously understood. In order to examine the effects of isoflurane on cocaine-sensitization, we administered cocaine (15 mg/kg i.p) or saline to adult male and female Sprague-Dawley rats for 9 days; on day 10, half of the rats were subjected to isoflurane anesthesia and the other half did not receive anesthesia. On day 11, rats were given their last dose of either cocaine or saline. We recorded behaviors for 1h on days 1, 9 and 11. Locomotor activity and stereotyped behaviors were quantified using photo beam monitors and the scoring of video tapes, respectively. Results indicated that a single exposure to isoflurane significantly dampens the stereotypic behavior associated with repeated cocaine administration in females but not in males. They further suggest that either GABA or glutamate play more prominent roles in cocaine-sensitization behavior in females than in males.
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Affiliation(s)
- Nora Siegal
- Department of Physiology and Pharmacology, Program on Neural and Behavioral Sciences, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA
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Zhao Y, Sun L. Antidepressants modulate the in vitro inhibitory effects of propofol and ketamine on norepinephrine and serotonin transporter function. J Clin Neurosci 2008; 15:1264-9. [PMID: 18815045 DOI: 10.1016/j.jocn.2007.11.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 11/04/2007] [Accepted: 11/05/2007] [Indexed: 11/18/2022]
Abstract
Norepinephrine transporter (NET) and serotonin transporter (SERT) proteins regulate norepinephrine (NE) and serotonin via their reuptake function and are targets of antidepressants action. Several intravenous (IV) anesthetics have been shown to inhibit NET and SERT. The interactions between antidepressants and anesthetics on transporter function, however, are not well studied. We examined the effect of different IV anesthetics on NET and SERT function, with and without chronic antidepressant pretreatment, by measuring NE or 5-hydroxytryptamine (5-HT) uptake and determined NET and SERT protein expression via immunoblotting. Both ketamine and propofol inhibited NET dose-dependently (propofol 10(-4)M -22%+/-5.6%, and propofol 10(-3)M -35%+/-5.7%; ketamine 10(-4)M -23%+/-4.1% and ketamine 10(-3)M -73%+/-2.9%); and SERT (propofol 10(-4)M -11%+/-4.3% and propofol 10(-3)M -23%+/-3.8%; ketamine 10(-4)M -29%+/-5.2% and ketamine 10(-3)M -63%+/-6.4%). Etomidate and thiopental had no effect on either NET or SERT function. Desipramine and fluoxetine, specific inhibitors of NET and SERT, respectively, both enhanced the inhibitory effects of propofol but reduced the inhibitory effects of ketamine on NET and SERT functions. IV anesthetics treatment did not change transporter protein expression in the presence of its respective inhibitor. Our results demonstrate that both ketamine and propofol inhibited SERT and NET function, but the inhibition was differentially modulated by antidepressants. Therefore, in the clinical context, this would suggest that patients receiving antidepressant treatments might have altered response to IV anesthetics in an agent-specific manner.
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Affiliation(s)
- Yejun Zhao
- Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, New York, USA
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Ko BH, Paik JY, Jung KH, Bae JS, Lee EJ, Choe YS, Kim BT, Lee KH. Effects of anesthetic agents on cellular 123I-MIBG transport and in vivo 123I-MIBG biodistribution. Eur J Nucl Med Mol Imaging 2007; 35:554-61. [DOI: 10.1007/s00259-007-0605-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 09/02/2007] [Indexed: 12/01/2022]
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Diniz PHC, Silva JH, Gomez MV, Guatimosim C, Gomez RS. Halothane Increases Non-vesicular [3H]dopamine Release from Brain Cortical Slices. Cell Mol Neurobiol 2007; 27:757-70. [PMID: 17680357 DOI: 10.1007/s10571-007-9162-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Accepted: 06/11/2007] [Indexed: 10/23/2022]
Abstract
Experimental data suggest that halothane anesthesia is associated with significant changes in dopamine (DA) concentration in some brain regions but the mechanism of this effect is not well known. Rat brain cortical slices were labeled with [(3)H]DA to further characterize the effects of halothane on the release of this neurotransmitter from the central nervous system. Halothane induced an increase on the release of [(3)H]DA that was dependent on incubation time and anesthetic concentration (0.012, 0.024, 0.048, 0.072 and 0.096 mM). This effect was independent of extracellular or intracellular calcium. In addition, [(3)H]DA release evoked by halothane was not affected by TTX (blocker of voltage-dependent Na(+) channels) or reserpine (a blocker of vesicular monoamine transporter). These data suggest that [(3)H]DA release induced by halothane is non-vesicular and would be mediated by the dopamine transporter (DAT) and norepinephrine transporter (NET). GBR 12909 and nomifensine, inhibitors of DAT, decreased the release of [(3)H]DA evoked by halothane. Nisoxetine, a blocker of NET, reduced the release of [(3)H]DA induced by halothane. In addition, GBR 12909, nisoxetine and, halothane decrease the uptake of [(3)H]DA into rat brain cortical slices. A decrease on halothane-induced release of [(3)H]DA was also observed when the brain cortical slices were incubated at low temperature and low extracellular sodium, which are known to interfere with the carrier-mediated release of the neurotransmitter. Ouabain, a Na(+)/K(+) ATPase pump inhibitor, which induces DA release through reverse transport, decreased [(3)H]DA release induced by halothane. It is suggested that halothane increases [(3)H]DA release in brain cortical slices that is mediated by DAT and NET present in the plasma membrane.
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Affiliation(s)
- Paulo H C Diniz
- Department of Pharmacology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Silva JH, Gomez RS, Diniz PHC, Gomez MV, Guatimosim C. The effect of sevoflurane on the release of [3H]dopamine from rat brain cortical slices. Brain Res Bull 2007; 72:309-14. [PMID: 17452291 DOI: 10.1016/j.brainresbull.2007.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 01/17/2007] [Indexed: 12/20/2022]
Abstract
Dopamine is a neurotransmitter that exerts major control on important brain functions and some lines of studies suggest that dopaminergic neurotransmission may be a potential target for volatile anesthetics. In the present study, rat brain cortical slices were labeled with [(3)H]dopamine to investigate the effects of sevoflurane on the release of this neurotransmitter. [(3)H]dopamine release was significantly increased in the presence of sevoflurane (0.46 mM) and this effect was independent of extracellular or intracellular calcium. In addition, [(3)H]dopamine release evoked by sevoflurane was not affected by TTX (blocker of voltage-dependent sodium channels) or reserpine (a blocker of the vesicular monoamine transporter). These data suggest that the dopamine release induced by sevoflurane is non-vesicular, independent of exocytosis and, would be mediated by the dopamine transporter (DAT). GBR12909 and nomifensine, inhibitors of DAT, decreased the release of [(3)H]dopamine evoked by sevoflurane. The same effect was also observed when the brain cortical slices were incubated at low temperature and low extracellular sodium. Ouabain, a Na(+)/K(+) ATPase pump inhibitor, which is known to induce dopamine release through reverse transport, decreased [(3)H]dopamine release induced by sevoflurane. In conclusion, the present study suggests that sevoflurane increases [(3)H]dopamine release in brain cortical slices that is mediated by DAT located at the plasma membrane.
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Affiliation(s)
- Janice H Silva
- Department of Pharmacology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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Yamaoka I, Doi M, Nakayama M, Ozeki A, Mochizuki S, Sugahara K, Yoshizawa F. Intravenous administration of amino acids during anesthesia stimulates muscle protein synthesis and heat accumulation in the body. Am J Physiol Endocrinol Metab 2006; 290:E882-8. [PMID: 16352675 DOI: 10.1152/ajpendo.00333.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study was conducted to determine the contribution of muscle protein synthesis to the prevention of anesthesia-induced hypothermia by intravenous administration of an amino acid (AA) mixture. We examined the changes of intraperitoneal temperature (Tcore) and the rates of protein synthesis (K(s)) and the phosphorylation states of translation initiation regulators and their upstream signaling components in skeletal muscle in conscious (Nor) or propofol-anesthetized (Ane) rats after a 3-h intravenous administration of a balanced AA mixture or saline (Sal). Compared with Sal administration, the AA mixture administration markedly attenuated the decrease in Tcore in rats during anesthesia, whereas Tcore in the Nor-AA group became slightly elevated during treatment. Stimulation of muscle protein synthesis resulting from AA administration was observed in each case, although K(s) remained lower in the Ane-AA group than in the Nor-Sal group. AA administration during anesthesia significantly increased insulin concentrations to levels approximately 6-fold greater than in the Nor-AA group and enhanced phosphorylation of eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) and ribosomal protein S6 protein kinase relative to all other groups and treatments. The alterations in the Ane-AA group were accompanied by hyperphosphorylation of protein kinase B and the mammalian target of rapamycin (mTOR). These results suggest that administration of an AA mixture during anesthesia stimulates muscle protein synthesis via insulin-mTOR-dependent activation of translation initiation regulators caused by markedly elevated insulin and, thereby, facilitates thermal accumulation in the body.
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Affiliation(s)
- Ippei Yamaoka
- Division of Pharmacology, Drug Safety and Metabolism, Otsuka Pharmaceutical Factory, Naruto, Tokushima 772-8601, Japan.
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Doudet DJ, Rosa-Neto P, Munk OL, Ruth TJ, Jivan S, Cumming P. Effect of age on markers for monoaminergic neurons of normal and MPTP-lesioned rhesus monkeys: A multi-tracer PET study. Neuroimage 2006; 30:26-35. [PMID: 16378735 DOI: 10.1016/j.neuroimage.2005.09.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 08/31/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022] Open
Abstract
The binding of three tracers for monoaminergic terminals was mapped in the brain of healthy young (N=6) and healthy old rhesus monkeys (N=4), aged monkeys with mild unilateral intracarotid MPTP lesions (N=3), and monkeys of intermediate age with severe systemic MPTP lesions (N=6). The ligand for monoaminergic vesicles (+)-[(11)C]dihydrotetrabenazine (+DTBZ) had a mean binding potential (pB) of 1.4 in striatum of the healthy young monkeys, which was reduced by 20% in putamen of the old monkeys. The catecholamine transporter ligand (+)-[(11)C]methylphenidate (+MP) had a mean pB of 1.3 in striatum of the young monkeys, which was reduced by 40% in caudate and putamen of the old monkeys. The DOPA decarboxylase substrate [(18)F]fluoro-l-DOPA (FDOPA) had a mean decarboxylation coefficient (k(3)(S)) of 0.4 h(-1) in striatum of the young group, and was not significantly reduced in the aged group. Of the three ligands, only +DTBZ pB was significantly reduced in striatum of the small group of animals with mild unilateral lesions. In the group with systemic MPTP lesions, the mean reduction of the binding of the three ligands was 80% in the caudate and putamen. However, the decline in +MP pB in the ventral striatum (-75%) exceeded the declines of +DTBZ pB and FDOPA k(3)(S) in that region (-65%), suggesting that compensatory down-modulation of uptake sites may occur in the striatal regions with the least dopamine depletion. Binding of all three ligands was reduced by 50% in the anterior cingulate cortex and in the thalamus, suggesting toxicity of MPTP for extrastriatal catecholamine innervations. +DTBZ binding in the hypothalamus, presumably mainly in serotonin fibers, was unaffected by systemic MPTP treatment. Of the three tracers, +DTBZ was most sensitive for detecting MPTP-induced dopamine depletion in monkey striatum.
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Affiliation(s)
- Doris J Doudet
- Department Medicine/Neurology and UBC/TRIUMFPET Program, University of British Columbia, Vancouver, Canada
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