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Rada P, Hrdý I, Zdrha A, Narayanasamy RK, Smutná T, Horáčková J, Harant K, Beneš V, Ong SC, Tsai CY, Luo HW, Chiu CH, Tang P, Tachezy J. Double-Stranded RNA Viruses Are Released From Trichomonas vaginalis Inside Small Extracellular Vesicles and Modulate the Exosomal Cargo. Front Microbiol 2022; 13:893692. [PMID: 35602021 PMCID: PMC9114709 DOI: 10.3389/fmicb.2022.893692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Trichomonas vaginalis is a parasitic protist that infects the human urogenital tract. During the infection, trichomonads adhere to the host mucosa, acquire nutrients from the vaginal/prostate environment, and release small extracellular vesicles (sEVs) that contribute to the trichomonad adherence and modulate the host-parasite communication. Approximately 40–70% of T. vaginalis strains harbor a double-stranded RNA virus called Trichomonasvirus (TVV). Naked TVV particles have the potential to stimulate a proinflammatory response in human cells, however, the mode of TVV release from trichomonads to the environment is not clear. In this report, we showed for the first time that TVV particles are released from T. vaginalis cells within sEVs. The sEVs loaded with TVV stimulated a higher proinflammatory response of human HaCaT cells in comparison to sEVs from TVV negative parasites. Moreover, a comparison of T. vaginalis isogenic TVV plus and TVV minus clones revealed a significant impact of TVV infection on the sEV proteome and RNA cargo. Small EVs from TVV positive trichomonads contained 12 enriched and 8 unique proteins including membrane-associated BspA adhesine, and about a 2.5-fold increase in the content of small regulatory tsRNA. As T. vaginalis isolates are frequently infected with TVV, the release of TVV via sEVs to the environment represents an important factor with the potential to enhance inflammation-related pathogenesis during trichomoniasis.
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Affiliation(s)
- Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Alois Zdrha
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Ravi Kumar Narayanasamy
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Tamara Smutná
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Jana Horáčková
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Karel Harant
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
| | - Vladimír Beneš
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Seow-Chin Ong
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Yu Tsai
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Hong-Wei Luo
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Hsun Chiu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Petrus Tang
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, Biotechnology and Biomedicine Center in Vestec (BIOCEV), Vestec, Czechia
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Ong SC, Cheng WH, Ku FM, Tsai CY, Huang PJ, Lee CC, Yeh YM, Rada P, Hrdý I, Narayanasamy RK, Smutná T, Lin R, Luo HW, Chiu CH, Tachezy J, Tang P. Identification of Endosymbiotic Virus in Small Extracellular Vesicles Derived from Trichomonas vaginalis. Genes (Basel) 2022; 13:genes13030531. [PMID: 35328084 PMCID: PMC8951798 DOI: 10.3390/genes13030531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 02/07/2023] Open
Abstract
Accumulated evidence suggests that the endosymbiotic Trichomonasvirus (TVV) may play a role in the pathogenesis and drug susceptibility of Trichomonas vaginalis. Several reports have shown that extracellular vesicles (EVs) released from TVV-positive (TVV+) trichomonads can modulate the immune response in human vaginal epithelial cells and animal models. These results prompted us to examine whether EVs released from TVV+ isolates contained TVV. We isolated small extracellular vesicles (sEVs) from six T. vaginalis isolates that were either TVV free (ATCC 50143), harbored a single (ATCC 30236, ATCC 30238, T1), two (ATCC PRA-98), or three TVV subspecies (ATCC 50148). The presence of TVV subspecies in the six isolates was observed using reverse transcription-polymerase chain reaction (RT-PCR). Transmission electron microscopy (TEM) confirmed the presence of cup-shaped sEVs with a size range from 30–150 nm. Trichomonas vaginalis tetraspanin (TvTSP1; TVAG_019180), the classical exosome marker, was identified in all the sEV preparations. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed that all the sEVs isolated from TVV+ isolates contain viral capsid proteins derived from the same TVV subspecies in that isolate as demonstrated by RT-PCR. To provide more comprehensive information on the TVV subspecies population in other T. vaginalis isolates, we investigated the distribution of TVV subspecies in twenty-four isolates by mining the New-Generation Sequencing (NGS) RNAseq datasets. Our results should be beneficial for future studies investigating the role of TVV on the pathogenicity of T. vaginalis and the possible transmission of virus subspecies among different isolates via sEVs.
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Affiliation(s)
- Seow-Chin Ong
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
| | - Wei-Hung Cheng
- Department of Medical Laboratory Science, College of Medical Science and Technology, I-Shou University, Kaohsiung 824, Taiwan;
| | - Fu-Man Ku
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
| | - Chih-Yu Tsai
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
| | - Po-Jung Huang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan District, Taoyuan 333, Taiwan;
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333, Taiwan; (C.-C.L.); (Y.-M.Y.)
| | - Chi-Ching Lee
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333, Taiwan; (C.-C.L.); (Y.-M.Y.)
- Department of Computer Science and Information Engineering, College of Engineering, Chang Gung University, Taoyuan 333, Taiwan
| | - Yuan-Ming Yeh
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333, Taiwan; (C.-C.L.); (Y.-M.Y.)
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University in Vestec (BIOCEV), Průmyslová 595, 252 42 Vestec, Czech Republic; (P.R.); (I.H.); (R.K.N.); (T.S.)
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University in Vestec (BIOCEV), Průmyslová 595, 252 42 Vestec, Czech Republic; (P.R.); (I.H.); (R.K.N.); (T.S.)
| | - Ravi Kumar Narayanasamy
- Department of Parasitology, Faculty of Science, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University in Vestec (BIOCEV), Průmyslová 595, 252 42 Vestec, Czech Republic; (P.R.); (I.H.); (R.K.N.); (T.S.)
| | - Tamara Smutná
- Department of Parasitology, Faculty of Science, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University in Vestec (BIOCEV), Průmyslová 595, 252 42 Vestec, Czech Republic; (P.R.); (I.H.); (R.K.N.); (T.S.)
| | - Rose Lin
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
| | - Hong-Wei Luo
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
| | - Cheng-Hsun Chiu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333, Taiwan;
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University in Vestec (BIOCEV), Průmyslová 595, 252 42 Vestec, Czech Republic; (P.R.); (I.H.); (R.K.N.); (T.S.)
- Correspondence: (J.T.); (P.T.)
| | - Petrus Tang
- Department of Parasitology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (S.-C.O.); (F.-M.K.); (C.-Y.T.); (R.L.); (H.-W.L.)
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333, Taiwan;
- Correspondence: (J.T.); (P.T.)
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Zimmann N, Rada P, Žárský V, Smutná T, Záhonová K, Dacks J, Harant K, Hrdý I, Tachezy J. Proteomic Analysis of Trichomonas vaginalis Phagolysosome, Lysosomal Targeting, and Unconventional Secretion of Cysteine Peptidases. Mol Cell Proteomics 2022; 21:100174. [PMID: 34763061 PMCID: PMC8717582 DOI: 10.1016/j.mcpro.2021.100174] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/25/2021] [Accepted: 11/04/2021] [Indexed: 11/25/2022] Open
Abstract
The lysosome represents a central degradative compartment of eukaryote cells, yet little is known about the biogenesis and function of this organelle in parasitic protists. Whereas the mannose 6-phosphate (M6P)-dependent system is dominant for lysosomal targeting in metazoans, oligosaccharide-independent sorting has been reported in other eukaryotes. In this study, we investigated the phagolysosomal proteome of the human parasite Trichomonas vaginalis, its protein targeting and the involvement of lysosomes in hydrolase secretion. The organelles were purified using Percoll and OptiPrep gradient centrifugation and a novel purification protocol based on the phagocytosis of lactoferrin-covered magnetic nanoparticles. The analysis resulted in a lysosomal proteome of 462 proteins, which were sorted into 21 classes. Hydrolases represented the largest functional class and included proteases, lipases, phosphatases, and glycosidases. Identification of a large set of proteins involved in vesicular trafficking (80) and turnover of actin cytoskeleton rearrangement (29) indicate a dynamic phagolysosomal compartment. Several cysteine proteases such as TvCP2 were previously shown to be secreted. Our experiments showed that secretion of TvCP2 was strongly inhibited by chloroquine, which increases intralysosomal pH, thus indicating that TvCP2 secretion occurs through lysosomes rather than the classical secretory pathway. Unexpectedly, we identified divergent homologues of the M6P receptor TvMPR in the phagolysosomal proteome, although T. vaginalis lacks enzymes for M6P formation. To test whether oligosaccharides are involved in lysosomal targeting, we selected the lysosome-resident cysteine protease CLCP, which possesses two glycosylation sites. Mutation of any of the sites redirected CLCP to the secretory pathway. Similarly, the introduction of glycosylation sites to secreted β-amylase redirected this protein to lysosomes. Thus, unlike other parasitic protists, T. vaginalis seems to utilize glycosylation as a recognition marker for lysosomal hydrolases. Our findings provide the first insight into the complexity of T. vaginalis phagolysosomes, their biogenesis, and role in the unconventional secretion of cysteine peptidases.
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Affiliation(s)
- Nadine Zimmann
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Tamara Smutná
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Kristína Záhonová
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Joel Dacks
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic; Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Karel Harant
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic.
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Verner Z, Žárský V, Le T, Narayanasamy RK, Rada P, Rozbeský D, Makki A, Belišová D, Hrdý I, Vancová M, Lender C, König C, Bruchhaus I, Tachezy J. Anaerobic peroxisomes in Entamoeba histolytica metabolize myo-inositol. PLoS Pathog 2021; 17:e1010041. [PMID: 34780573 PMCID: PMC8629394 DOI: 10.1371/journal.ppat.1010041] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 11/29/2021] [Accepted: 10/18/2021] [Indexed: 11/19/2022] Open
Abstract
Entamoeba histolytica is believed to be devoid of peroxisomes, like most anaerobic protists. In this work, we provided the first evidence that peroxisomes are present in E. histolytica, although only seven proteins responsible for peroxisome biogenesis (peroxins) were identified (Pex1, Pex6, Pex5, Pex11, Pex14, Pex16, and Pex19). Targeting matrix proteins to peroxisomes is reduced to the PTS1-dependent pathway mediated via the soluble Pex5 receptor, while the PTS2 receptor Pex7 is absent. Immunofluorescence microscopy showed that peroxisomal markers (Pex5, Pex14, Pex16, Pex19) are present in vesicles distinct from mitosomes, the endoplasmic reticulum, and the endosome/phagosome system, except Pex11, which has dual localization in peroxisomes and mitosomes. Immunoelectron microscopy revealed that Pex14 localized to vesicles of approximately 90-100 nm in diameter. Proteomic analyses of affinity-purified peroxisomes and in silico PTS1 predictions provided datasets of 655 and 56 peroxisomal candidates, respectively; however, only six proteins were shared by both datasets, including myo-inositol dehydrogenase (myo-IDH). Peroxisomal NAD-dependent myo-IDH appeared to be a dimeric enzyme with high affinity to myo-inositol (Km 0.044 mM) and can utilize also scyllo-inositol, D-glucose and D-xylose as substrates. Phylogenetic analyses revealed that orthologs of myo-IDH with PTS1 are present in E. dispar, E. nutalli and E. moshkovskii but not in E. invadens, and form a monophyletic clade of mostly peroxisomal orthologs with free-living Mastigamoeba balamuthi and Pelomyxa schiedti. The presence of peroxisomes in E. histolytica and other archamoebae breaks the paradigm of peroxisome absence in anaerobes and provides a new potential target for the development of antiparasitic drugs.
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Affiliation(s)
- Zdeněk Verner
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Tien Le
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Ravi Kumar Narayanasamy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Daniel Rozbeský
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Darja Belišová
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Marie Vancová
- Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Ceske Budejovice, Czech Republic
| | - Corinna Lender
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Constantin König
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
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Narayanasamy RK, Rada P, Zdrha A, van Ranst M, Neyts J, Tachezy J. Cytidine nucleoside analog is an effective antiviral drug against Trichomonasvirus. J Microbiol Immunol Infect 2021; 55:191-198. [PMID: 34479802 DOI: 10.1016/j.jmii.2021.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/09/2021] [Accepted: 08/19/2021] [Indexed: 01/25/2023]
Abstract
BACKGROUND Trichomonas vaginalis is the causative agent of a sexually transmitted disease in humans. The virulence of the parasite depends on multiple factors, including the presence of endosymbiotic dsRNA viruses. The presence of Trichomonasviruses (TVV) was associated with more severe genital symptoms, increased proinflammatory host reactions, and modulated parasite sensitivity to metronidazole. However, no efficient antiviral drugs are available against TVV to derive isogenic TVV-positive and TVV-negative cell lines that are essential for investigations of the TVV impact on T. vaginalis biology. METHODS 7-Deaza-2'-C-methyladenosine (7d2CMA) and 2'-C-methylcytidine (2CMC) were used for TVV inhibitory assay. TVV replication was monitored using quantitative reverse transcription PCR (RT qPCR) and western blotting. Modeling of TVV1 RNA-dependent RNA polymerase (RdRp) was performed to visualize the inhibitor-RdRp interaction. Susceptibility to metronidazole was performed under aerobic and anaerobic conditions. RESULTS We demonstrated that 2CMC but not 7d2CMA is a potent inhibitor of TVV replication. Molecular modeling suggested that the RdRp active site can accommodate 2CMC in the active triphosphate nucleotide form. The effect of 2CMC was shown on strains infected with a single and multiple TVV species. The optimal 2CMC concentration (10 μM) demonstrated strong selectivity for TVVs over trichomonad growth. The presence of TVV has no effect on T. vaginalis metronidazole susceptibility in derived isogenic cell lines. CONCLUSIONS 2CMC acts against TVVs and represents a new inhibitor against Totiviridae viruses. Our isogenic clones are now available for further studies of various aspects of T. vaginalis biology related to TVV infection.
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Affiliation(s)
- Ravi Kumar Narayanasamy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic.
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic.
| | - Alois Zdrha
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic.
| | - Marc van Ranst
- Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Belgium.
| | - Johan Neyts
- Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Belgium.
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic.
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Le T, Žárský V, Nývltová E, Rada P, Harant K, Vancová M, Verner Z, Hrdý I, Tachezy J. Anaerobic peroxisomes in Mastigamoeba balamuthi. Proc Natl Acad Sci U S A 2020; 117:2065-2075. [PMID: 31932444 PMCID: PMC6994998 DOI: 10.1073/pnas.1909755117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The adaptation of eukaryotic cells to anaerobic conditions is reflected by substantial changes to mitochondrial metabolism and functional reduction. Hydrogenosomes belong among the most modified mitochondrial derivative and generate molecular hydrogen concomitant with ATP synthesis. The reduction of mitochondria is frequently associated with loss of peroxisomes, which compartmentalize pathways that generate reactive oxygen species (ROS) and thus protect against cellular damage. The biogenesis and function of peroxisomes are tightly coupled with mitochondria. These organelles share fission machinery components, oxidative metabolism pathways, ROS scavenging activities, and some metabolites. The loss of peroxisomes in eukaryotes with reduced mitochondria is thus not unexpected. Surprisingly, we identified peroxisomes in the anaerobic, hydrogenosome-bearing protist Mastigamoeba balamuthi We found a conserved set of peroxin (Pex) proteins that are required for protein import, peroxisomal growth, and division. Key membrane-associated Pexs (MbPex3, MbPex11, and MbPex14) were visualized in numerous vesicles distinct from hydrogenosomes, the endoplasmic reticulum (ER), and Golgi complex. Proteomic analysis of cellular fractions and prediction of peroxisomal targeting signals (PTS1/PTS2) identified 51 putative peroxisomal matrix proteins. Expression of selected proteins in Saccharomyces cerevisiae revealed specific targeting to peroxisomes. The matrix proteins identified included components of acyl-CoA and carbohydrate metabolism and pyrimidine and CoA biosynthesis, whereas no components related to either β-oxidation or catalase were present. In conclusion, we identified a subclass of peroxisomes, named "anaerobic" peroxisomes that shift the current paradigm and turn attention to the reductive evolution of peroxisomes in anaerobic organisms.
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Affiliation(s)
- Tien Le
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Eva Nývltová
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Karel Harant
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Marie Vancová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic
| | - Zdeněk Verner
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, BIOCEV, Charles University, 25242 Vestec, Czech Republic;
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Rada P, Kellerová P, Verner Z, Tachezy J. Investigation of the Secretory Pathway inTrichomonas vaginalisArgues against a Moonlighting Function of Hydrogenosomal Enzymes. J Eukaryot Microbiol 2019; 66:899-910. [DOI: 10.1111/jeu.12741] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 05/01/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Petr Rada
- Department of Parasitology Faculty of Science Charles University, BIOCEV Průmyslová 595 Vestec 25242 Czech Republic
| | - Pavlína Kellerová
- Department of Parasitology Faculty of Science Charles University, BIOCEV Průmyslová 595 Vestec 25242 Czech Republic
| | - Zdeněk Verner
- Department of Parasitology Faculty of Science Charles University, BIOCEV Průmyslová 595 Vestec 25242 Czech Republic
| | - Jan Tachezy
- Department of Parasitology Faculty of Science Charles University, BIOCEV Průmyslová 595 Vestec 25242 Czech Republic
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Rada P, Makki A, Žárský V, Tachezy J. Targeting of tail-anchored proteins to Trichomonas vaginalis hydrogenosomes. Mol Microbiol 2019; 111:588-603. [PMID: 30506591 DOI: 10.1111/mmi.14175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2018] [Indexed: 01/17/2023]
Abstract
Tail-anchored (TA) proteins are membrane proteins that are found in all domains of life. They consist of an N-terminal domain that performs various functions and a single transmembrane domain (TMD) near the C-terminus. In eukaryotes, TA proteins are targeted to the membranes of mitochondria, the endoplasmic reticulum (ER), peroxisomes and in plants, chloroplasts. The targeting of these proteins to their specific destinations correlates with the properties of the C-terminal domain, mainly the TMD hydrophobicity and the net charge of the flanking regions. Trichomonas vaginalis is a human parasite that has adapted to oxygen-poor environment. This adaptation is reflected by the presence of highly modified mitochondria (hydrogenosomes) and the absence of peroxisomes. The proteome of hydrogenosomes is considerably reduced; however, our bioinformatic analysis predicted 120 putative hydrogenosomal TA proteins. Seven proteins were selected to prove their localization. The elimination of the net positive charge in the C-tail of the hydrogenosomal TA4 protein resulted in its dual localization to hydrogenosomes and the ER, causing changes in ER morphology. Domain mutation and swap experiments with hydrogenosomal (TA4) and ER (TAPDI) proteins indicated that the general principles for specific targeting are conserved across eukaryotic lineages, including T. vaginalis; however, there are also significant lineage-specific differences.
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Affiliation(s)
- Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, Vestec, 25242, Czech Republic
| | - Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, Vestec, 25242, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, Vestec, 25242, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, Vestec, 25242, Czech Republic
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9
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Makki A, Rada P, Žárský V, Kereïche S, Kováčik L, Novotný M, Jores T, Rapaport D, Tachezy J. Triplet-pore structure of a highly divergent TOM complex of hydrogenosomes in Trichomonas vaginalis. PLoS Biol 2019; 17:e3000098. [PMID: 30608924 PMCID: PMC6334971 DOI: 10.1371/journal.pbio.3000098] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/16/2019] [Accepted: 12/11/2018] [Indexed: 11/30/2022] Open
Abstract
Mitochondria originated from proteobacterial endosymbionts, and their transition to organelles was tightly linked to establishment of the protein import pathways. The initial import of most proteins is mediated by the translocase of the outer membrane (TOM). Although TOM is common to all forms of mitochondria, an unexpected diversity of subunits between eukaryotic lineages has been predicted. However, experimental knowledge is limited to a few organisms, and so far, it remains unsettled whether the triplet-pore or the twin-pore structure is the generic form of TOM complex. Here, we analysed the TOM complex in hydrogenosomes, a metabolically specialised anaerobic form of mitochondria found in the excavate Trichomonas vaginalis. We demonstrate that the highly divergent β-barrel T. vaginalis TOM (TvTom)40-2 forms a translocation channel to conduct hydrogenosomal protein import. TvTom40-2 is present in high molecular weight complexes, and their analysis revealed the presence of four tail-anchored (TA) proteins. Two of them, Tom36 and Tom46, with heat shock protein (Hsp)20 and tetratricopeptide repeat (TPR) domains, can bind hydrogenosomal preproteins and most likely function as receptors. A third subunit, Tom22-like protein, has a short cis domain and a conserved Tom22 transmembrane segment but lacks a trans domain. The fourth protein, hydrogenosomal outer membrane protein 19 (Homp19) has no known homology. Furthermore, our data indicate that TvTOM is associated with sorting and assembly machinery (Sam)50 that is involved in β-barrel assembly. Visualisation of TvTOM by electron microscopy revealed that it forms three pores and has an unconventional skull-like shape. Although TvTOM seems to lack Tom7, our phylogenetic profiling predicted Tom7 in free-living excavates. Collectively, our results suggest that the triplet-pore TOM complex, composed of three conserved subunits, was present in the last common eukaryotic ancestor (LECA), while receptors responsible for substrate binding evolved independently in different eukaryotic lineages. The highly divergent outer membrane translocase (TOM) from the Trichomonas hydrogenosome (an organelle related to mitochondria) is composed of conserved core and lineage-specific subunits, and has an unconventional skull-like triplet-pore structure. Mitochondria carry out many vital functions in the eukaryotic cells, from energy metabolism to programmed cell death. These organelles descended from bacterial endosymbionts, and during their evolution, the cell established a mechanism to transport nuclear-encoded proteins into mitochondria. Embedded in the mitochondrial outer membrane is a molecular machine, known as the translocase of the outer membrane (TOM) complex, that plays a key role in protein import and biogenesis of the organelle. Here, we provide evidence that the TOM complex of hydrogenosomes, a metabolically specialised anaerobic form of mitochondria in Trichomonas vaginalis, is composed of highly divergent core subunits and lineage-specific peripheral subunits. Despite the evolutionary distance, the T. vaginalis TOM (TvTOM) complex has a conserved triplet-pore structure but with a unique skull-like shape suggesting that the TOM in the early mitochondrion could have formed three pores. Our results contribute to a better understanding of the evolution and adaptation of protein import machinery in anaerobic forms of mitochondria.
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Affiliation(s)
- Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Sami Kereïche
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Lubomír Kováčik
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marian Novotný
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Tobias Jores
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
- * E-mail:
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10
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Betancourt L, Rada P, Hernandez L, Araujo H, Ceballos G, Hernandez L, Tucci P, Mari Z, De Pasquale M, Paredes D. Micellar electrokinetic chromatography with laser induced fluorescence detection shows increase of putrescine in erythrocytes of Parkinson's disease patients. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1081-1082:51-57. [DOI: 10.1016/j.jchromb.2018.02.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/26/2017] [Accepted: 02/10/2018] [Indexed: 01/09/2023]
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11
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Štáfková J, Rada P, Meloni D, Žárský V, Smutná T, Zimmann N, Harant K, Pompach P, Hrdý I, Tachezy J. Dynamic secretome of Trichomonas vaginalis: Case study of β-amylases. Mol Cell Proteomics 2018; 17:304-320. [PMID: 29233912 PMCID: PMC5795393 DOI: 10.1074/mcp.ra117.000434] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Indexed: 11/06/2022] Open
Abstract
The secretion of virulence factors by parasitic protists into the host environment plays a fundamental role in multifactorial host-parasite interactions. Several effector proteins are known to be secreted by Trichomonas vaginalis, a human parasite of the urogenital tract. However, a comprehensive profiling of the T. vaginalis secretome remains elusive, as do the mechanisms of protein secretion. In this study, we used high-resolution label-free quantitative MS to analyze the T. vaginalis secretome, considering that secretion is a time- and temperature-dependent process, to define the cutoff for secreted proteins. In total, we identified 2 072 extracellular proteins, 89 of which displayed significant quantitative increases over time at 37 °C. These 89 bona fide secreted proteins were sorted into 13 functional categories. Approximately half of the secreted proteins were predicted to possess transmembrane helixes. These proteins mainly include putative adhesins and leishmaniolysin-like metallopeptidases. The other half of the soluble proteins include several novel potential virulence factors, such as DNaseII, pore-forming proteins, and β-amylases. Interestingly, current bioinformatic tools predicted the secretory signal in only 18% of the identified T. vaginalis-secreted proteins. Therefore, we used β-amylases as a model to investigate the T. vaginalis secretory pathway. We demonstrated that two β-amylases (BA1 and BA2) are transported via the classical endoplasmic reticulum-to-Golgi pathways, and in the case of BA1, we showed that the protein is glycosylated with multiple N-linked glycans of Hex5HexNAc2 structure. The secretion was inhibited by brefeldin A but not by FLI-06. Another two β-amylases (BA3 and BA4), which are encoded in the T. vaginalis genome but absent from the secretome, were targeted to the lysosomal compartment. Collectively, under defined in vitro conditions, our analysis provides a comprehensive set of constitutively secreted proteins that can serve as a reference for future comparative studies, and it provides the first information about the classical secretory pathway in this parasite.
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Affiliation(s)
| | - Petr Rada
- From the ‡Department of Parasitology
| | | | | | | | | | | | - Petr Pompach
- §Institute of Biotechnology CAS, v. v. i., BIOCEV, Vestec, Czech Republic
- ¶Department of Biochemistry, Charles University, Faculty of Science, BIOCEV, Vestec, Czech Republic
| | - Ivan Hrdý
- From the ‡Department of Parasitology
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Garg S, Stölting J, Zimorski V, Rada P, Tachezy J, Martin WF, Gould SB. Conservation of Transit Peptide-Independent Protein Import into the Mitochondrial and Hydrogenosomal Matrix. Genome Biol Evol 2015; 7:2716-26. [PMID: 26338186 PMCID: PMC4607531 DOI: 10.1093/gbe/evv175] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The origin of protein import was a key step in the endosymbiotic acquisition of mitochondria. Though the main translocon of the mitochondrial outer membrane, TOM40, is ubiquitous among organelles of mitochondrial ancestry, the transit peptides, or N-terminal targeting sequences (NTSs), recognised by the TOM complex, are not. To better understand the nature of evolutionary conservation in mitochondrial protein import, we investigated the targeting behavior of Trichomonas vaginalis hydrogenosomal proteins in Saccharomyces cerevisiae and vice versa. Hydrogenosomes import yeast mitochondrial proteins even in the absence of their native NTSs, but do not import yeast cytosolic proteins. Conversely, yeast mitochondria import hydrogenosomal proteins with and without their short NTSs. Conservation of an NTS-independent mitochondrial import route from excavates to opisthokonts indicates its presence in the eukaryote common ancestor. Mitochondrial protein import is known to entail electrophoresis of positively charged NTSs across the electrochemical gradient of the inner mitochondrial membrane. Our present findings indicate that mitochondrial transit peptides, which readily arise from random sequences, were initially selected as a signal for charge-dependent protein targeting specifically to the mitochondrial matrix. Evolutionary loss of the electron transport chain in hydrogenosomes and mitosomes lifted the selective constraints that maintain positive charge in NTSs, allowing first the NTS charge, and subsequently the NTS itself, to be lost. This resulted in NTS-independent matrix targeting, which is conserved across the evolutionary divide separating trichomonads and yeast, and which we propose is the ancestral state of mitochondrial protein import.
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Affiliation(s)
- Sriram Garg
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jan Stölting
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Verena Zimorski
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Petr Rada
- Department of Parasitology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Charles University in Prague, Faculty of Science, Czech Republic
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Beltrán NC, Horváthová L, Jedelský PL, Šedinová M, Rada P, Marcinčiková M, Hrdý I, Tachezy J. Iron-induced changes in the proteome of Trichomonas vaginalis hydrogenosomes. PLoS One 2013; 8:e65148. [PMID: 23741475 PMCID: PMC3669245 DOI: 10.1371/journal.pone.0065148] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 04/17/2013] [Indexed: 12/02/2022] Open
Abstract
Iron plays a crucial role in metabolism as a key component of catalytic and redox cofactors, such as heme or iron-sulfur clusters in enzymes and electron-transporting or regulatory proteins. Limitation of iron availability by the host is also one of the mechanisms involved in immunity. Pathogens must regulate their protein expression according to the iron concentration in their environment and optimize their metabolic pathways in cases of limitation through the availability of respective cofactors. Trichomonas vaginalis, a sexually transmitted pathogen of humans, requires high iron levels for optimal growth. It is an anaerobe that possesses hydrogenosomes, mitochondrion-related organelles that harbor pathways of energy metabolism and iron-sulfur cluster assembly. We analyzed the proteomes of hydrogenosomes obtained from cells cultivated under iron-rich and iron-deficient conditions employing two-dimensional peptide separation combining IEF and nano-HPLC with quantitative MALDI-MS/MS. We identified 179 proteins, of which 58 were differentially expressed. Iron deficiency led to the upregulation of proteins involved in iron-sulfur cluster assembly and the downregulation of enzymes involved in carbohydrate metabolism. Interestingly, iron affected the expression of only some of multiple protein paralogues, whereas the expression of others was iron independent. This finding indicates a stringent regulation of differentially expressed multiple gene copies in response to changes in the availability of exogenous iron.
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Affiliation(s)
- Neritza Campo Beltrán
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Lenka Horváthová
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Petr L. Jedelský
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Miroslava Šedinová
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Petr Rada
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Michaela Marcinčiková
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
- * E-mail:
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14
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Rada P, Doležal P, Jedelský PL, Bursac D, Perry AJ, Šedinová M, Smíšková K, Novotný M, Beltrán NC, Hrdý I, Lithgow T, Tachezy J. The core components of organelle biogenesis and membrane transport in the hydrogenosomes of Trichomonas vaginalis. PLoS One 2011; 6:e24428. [PMID: 21935410 PMCID: PMC3174187 DOI: 10.1371/journal.pone.0024428] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 08/09/2011] [Indexed: 12/02/2022] Open
Abstract
Trichomonas vaginalis is a parasitic protist of the Excavata group. It contains an anaerobic form of mitochondria called hydrogenosomes, which produce hydrogen and ATP; the majority of mitochondrial pathways and the organellar genome were lost during the mitochondrion-to-hydrogenosome transition. Consequently, all hydrogenosomal proteins are encoded in the nucleus and imported into the organelles. However, little is known about the membrane machineries required for biogenesis of the organelle and metabolite exchange. Using a combination of mass spectrometry, immunofluorescence microscopy, in vitro import assays and reverse genetics, we characterized the membrane proteins of the hydrogenosome. We identified components of the outer membrane (TOM) and inner membrane (TIM) protein translocases include multiple paralogs of the core Tom40-type porins and Tim17/22/23 channel proteins, respectively, and uniquely modified small Tim chaperones. The inner membrane proteins TvTim17/22/23-1 and Pam18 were shown to possess conserved information for targeting to mitochondrial inner membranes, but too divergent in sequence to support the growth of yeast strains lacking Tim17, Tim22, Tim23 or Pam18. Full complementation was seen only when the J-domain of hydrogenosomal Pam18 was fused with N-terminal region and transmembrane segment of the yeast homolog. Candidates for metabolite exchange across the outer membrane were identified including multiple isoforms of the β-barrel proteins, Hmp35 and Hmp36; inner membrane MCF-type metabolite carriers were limited to five homologs of the ATP/ADP carrier, Hmp31. Lastly, hydrogenosomes possess a pathway for the assembly of C-tail-anchored proteins into their outer membrane with several new tail-anchored proteins being identified. These results show that hydrogenosomes and mitochondria share common core membrane components required for protein import and metabolite exchange; however, they also reveal remarkable differences that reflect the functional adaptation of hydrogenosomes to anaerobic conditions and the peculiar evolutionary history of the Excavata group.
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Affiliation(s)
- Petr Rada
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Pavel Doležal
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Petr L. Jedelský
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
- Laboratory of Mass Spectrometry, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Dejan Bursac
- Department of Biochemistry & Molecular Biology, Monash University, Melbourne, Australia
| | - Andrew J. Perry
- Department of Biochemistry & Molecular Biology, Monash University, Melbourne, Australia
| | - Miroslava Šedinová
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Kateřina Smíšková
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Marian Novotný
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Neritza Campo Beltrán
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Trevor Lithgow
- Department of Biochemistry & Molecular Biology, Monash University, Melbourne, Australia
| | - Jan Tachezy
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
- * E-mail:
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15
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Jedelský PL, Doležal P, Rada P, Pyrih J, Šmíd O, Hrdý I, Šedinová M, Marcinčiková M, Voleman L, Perry AJ, Beltrán NC, Lithgow T, Tachezy J. The minimal proteome in the reduced mitochondrion of the parasitic protist Giardia intestinalis. PLoS One 2011; 6:e17285. [PMID: 21390322 PMCID: PMC3044749 DOI: 10.1371/journal.pone.0017285] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 01/26/2011] [Indexed: 11/18/2022] Open
Abstract
The mitosomes of Giardia intestinalis are thought to be mitochondria highly-reduced in response to the oxygen-poor niche. We performed a quantitative proteomic assessment of Giardia mitosomes to increase understanding of the function and evolutionary origin of these enigmatic organelles. Mitosome-enriched fractions were obtained from cell homogenate using Optiprep gradient centrifugation. To distinguish mitosomal proteins from contamination, we used a quantitative shot-gun strategy based on isobaric tagging of peptides with iTRAQ and tandem mass spectrometry. Altogether, 638 proteins were identified in mitosome-enriched fractions. Of these, 139 proteins had iTRAQ ratio similar to that of the six known mitosomal markers. Proteins were selected for expression in Giardia to verify their cellular localizations and the mitosomal localization of 20 proteins was confirmed. These proteins include nine components of the FeS cluster assembly machinery, a novel diflavo-protein with NADPH reductase activity, a novel VAMP-associated protein, and a key component of the outer membrane protein translocase. None of the novel mitosomal proteins was predicted by previous genome analyses. The small proteome of the Giardia mitosome reflects the reduction in mitochondrial metabolism, which is limited to the FeS cluster assembly pathway, and a simplicity in the protein import pathway required for organelle biogenesis.
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Affiliation(s)
- Petr L. Jedelský
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Laboratory of Mass Spectrometry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Pavel Doležal
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jan Pyrih
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Ondřej Šmíd
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Miroslava Šedinová
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Michaela Marcinčiková
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Lubomír Voleman
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Andrew J. Perry
- Department of Biochemistry & Molecular Biology, Monash University, Clayton Campus, Melbourne, Australia
| | - Neritza Campo Beltrán
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Trevor Lithgow
- Department of Biochemistry & Molecular Biology, Monash University, Clayton Campus, Melbourne, Australia
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- * E-mail:
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16
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Rada P, Hernandez L, Hoebel BG. Feeding and systemic D-amphetamine increase extracellular acetylcholine in the medial thalamus: a possible reward enabling function. Neurosci Lett 2007; 416:184-7. [PMID: 17337121 DOI: 10.1016/j.neulet.2007.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 12/13/2006] [Accepted: 02/02/2007] [Indexed: 12/19/2022]
Abstract
Acetylcholine neurons that project forward from the midbrain are known to enable dopaminergic reward functions in the ventral tegmental area. The question is whether acetylcholine might also be released in the mediodorsal thalamus for the same general purposes. Rats with a microdialysis probe lodged in the mediodorsal thalamus were allowed to eat chow for 20 min after 16-h food deprivation or were given varying doses of D-amphetamine when fed ad libitum. The result in both cases was a significant increase in extracellular acetylcholine. During feeding, acetylcholine increased to 177% of baseline. In response to d-amphetamine (2.5 mg/kg), acetylcholine increased to 184%, and with a higher dose (5 mg/kg) to 400% of baseline. It is concluded that midbrain projections to limbic portions of the thalamus provide acetylcholine for behavioral activation. This cholinergic function theoretically plays a role in enabling the limbic circuits that pass through the thalamus for reinforcement of feeding and psychostimulant abuse.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, School of Medicine, University of Los Andes, Mérida 5101, Venezuela.
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17
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Rada P, Colasante C, Skirzewski M, Hernandez L, Hoebel B. Behavioral depression in the swim test causes a biphasic, long-lasting change in accumbens acetylcholine release, with partial compensation by acetylcholinesterase and muscarinic-1 receptors. Neuroscience 2006; 141:67-76. [PMID: 16677771 DOI: 10.1016/j.neuroscience.2006.03.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 03/17/2006] [Accepted: 03/23/2006] [Indexed: 11/20/2022]
Abstract
The nucleus accumbens may play a role in acquisition and expression of behavioral depression as measured using the inescapable swim test. Previous work shows that a local injection of a cholinergic muscarinic-1 receptor agonist increases immobility and a specific muscarinic-1 antagonist acts as an antidepressant-like drug by increasing swimming escape efforts. The present study used microdialysis to monitor extracellular acetylcholine levels in the accumbens, fluorescent labeled toxins to monitor changes in acetylcholinesterase and muscarinic-1 receptors, and semiquantitative-polymerase chain reaction to detect changes in gene expression for the muscarinic-1 receptor. Microdialysis showed that acetylcholine levels did not change while an animal was swimming; however, a significant transient decrease occurred when the rat was returned to the dialysis cage, followed by a long-lasting increase that reached a maximum three hours after the test. Acetylcholine levels stayed high even 24 h after the initial test as evidenced by a significant elevation in basal level prior to the second swim. This increase in neurotransmitter may have been partially compensated by a significant increase in the degradative enzyme, acetylcholinesterase, and by a decrease in muscarinic-1 receptors and their gene expression. These results further demonstrate the importance of accumbens cholinergic function in the appearance of a depression-like state.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, Medical School, University of Los Andes, Merida, Venezuela.
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18
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Hoebel B, Bocarsly M, Avena N, Rada P. WITHDRAWN: “Eating for dopamine: Effects of learning, weight loss, bingeing and purging”. Appetite 2006. [DOI: 10.1016/j.appet.2006.03.224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Avena NM, Rada P, Moise N, Hoebel BG. Sucrose sham feeding on a binge schedule releases accumbens dopamine repeatedly and eliminates the acetylcholine satiety response. Neuroscience 2006; 139:813-20. [PMID: 16460879 DOI: 10.1016/j.neuroscience.2005.12.037] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 12/12/2005] [Accepted: 12/22/2005] [Indexed: 12/31/2022]
Abstract
Drinking a sugar solution on an intermittent schedule can promote sugar bingeing and cause signs of dependence while releasing dopamine repeatedly like a drug of abuse. It is hypothesized that sweet taste alone is sufficient for this effect in sucrose bingeing rats. On the theory that acetylcholine in the nucleus accumbens plays a role in satiety, it is further hypothesized that purging the stomach contents will delay acetylcholine release. Rats with gastric fistulas and nucleus accumbens guide shafts for microdialysis were fed 12 h each day. During the first hour, fistulas were open for the sham-feeding group and closed for the real-feeding group, and 10% sucrose was the only food source. For the remaining 11 h, liquid rodent diet was available as well as the 10% sucrose to provide a balanced diet. In microdialysis tests during the first sugar meal on days 1, 2 and 21, extracellular dopamine increased at least 30% each day in both groups. Acetylcholine also increased during the sugar meals for the real-feeding animals, but not during sham feeding. In conclusion, the taste of sugar can increase extracellular dopamine in the nucleus accumbens without fail in animals on a dietary regimen that causes bingeing and sugar dependency. During sham feeding, the acetylcholine satiation signal is eliminated, and the animals drink more. These findings support the hypothesis that dopamine is released repeatedly in response to taste when bingeing on sweet food, and the acetylcholine satiety effect is greatly reduced by purging; this may be relevant to bulimia nervosa in humans.
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Affiliation(s)
- N M Avena
- Department of Psychology, Princeton University, Princeton, NJ 08540, USA
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20
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Dolezal P, Smíd O, Rada P, Zubácová Z, Bursać D, Suták R, Nebesárová J, Lithgow T, Tachezy J. Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting. Proc Natl Acad Sci U S A 2005; 102:10924-9. [PMID: 16040811 PMCID: PMC1182405 DOI: 10.1073/pnas.0500349102] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondria are archetypal organelles of endosymbiotic origin in eukaryotic cells. Some unicellular eukaryotes (protists) were considered to be primarily amitochondrial organisms that diverged from the eukaryotic lineage before the acquisition of the premitochondrial endosymbiont, but their amitochondrial status was recently challenged by the discovery of mitochondria-like double membrane-bound organelles called mitosomes. Here, we report that proteins targeted into mitosomes of Giardia intestinalis have targeting signals necessary and sufficient to be recognized by the mitosomal protein import machinery. Expression of these mitosomal proteins in Trichomonas vaginalis results in targeting to hydrogenosomes, a hydrogen-producing form of mitochondria. We identify, in Giardia and Trichomonas, proteins related to the component of the translocase in the inner membrane from mitochondria and the processing peptidase. A shared mode of protein targeting supports the hypothesis that mitosomes, hydrogenosomes, and mitochondria represent different forms of the same fundamental organelle having evolved under distinct selection pressures.
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Affiliation(s)
- Pavel Dolezal
- Department of Parasitology, Charles University, Vinicna 7, 128 44 Prague 2, Czech Republic
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21
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Schechter LE, Smith DL, Rosenzweig-Lipson S, Sukoff SJ, Dawson LA, Marquis K, Jones D, Piesla M, Andree T, Nawoschik S, Harder JA, Womack MD, Buccafusco J, Terry AV, Hoebel B, Rada P, Kelly M, Abou-Gharbia M, Barrett JE, Childers W. Lecozotan (SRA-333): A Selective Serotonin 1A Receptor Antagonist That Enhances the Stimulated Release of Glutamate and Acetylcholine in the Hippocampus and Possesses Cognitive-Enhancing Properties. J Pharmacol Exp Ther 2005; 314:1274-89. [PMID: 15951399 DOI: 10.1124/jpet.105.086363] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent data has suggested that the 5-hydroxytryptamine (5-HT)(1A) receptor is involved in cognitive processing. A novel 5-HT(1A) receptor antagonist, 4-cyano-N-{2R-[4-(2,3-dihydrobenzo[1,4]-dioxin-5-yl)-piperazin-1-yl]-propyl}-N-pyridin-2-yl-benzamide HCl (lecozotan), which has been characterized in multiple in vitro and in vivo pharmacological assays as a drug to treat cognitive dysfunction, is reported. In vitro binding and intrinsic activity determinations demonstrated that lecozotan is a potent and selective 5-HT(1A) receptor antagonist. Using in vivo microdialysis, lecozotan (0.3 mg/kg s.c.) antagonized the decrease in hippocampal extracellular 5-HT induced by a challenge dose (0.3 mg/kg s.c.) of 8-hydroxy-2-dipropylaminotetralin (8-OH-DPAT) and had no effects alone at doses 10-fold higher. Lecozotan significantly potentiated the potassium chloride-stimulated release of glutamate and acetylcholine in the dentate gyrus of the hippocampus. Chronic administration of lecozotan did not induce 5-HT(1A) receptor tolerance or desensitization in a behavioral model indicative of 5-HT(1A) receptor function. In drug discrimination studies, lecozotan (0.01-1 mg/kg i.m.) did not substitute for 8-OH-DPAT and produced a dose-related blockade of the 5-HT(1A) agonist discriminative stimulus cue. In aged rhesus monkeys, lecozotan produced a significant improvement in task performance efficiency at an optimal dose (1 mg/kg p.o.). Learning deficits induced by the glutamatergic antagonist MK-801 [(-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] (assessed by perceptually complex and visual spatial discrimination) and by specific cholinergic lesions of the hippocampus (assessed by visual spatial discrimination) were reversed by lecozotan (2 mg/kg i.m.) in marmosets. The heterosynaptic nature of the effects of lecozotan imbues this compound with a novel mechanism of action directed at the biochemical pathologies underlying cognitive loss in Alzheimer's disease.
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Affiliation(s)
- L E Schechter
- Wyeth, Neuroscience Discovery Research, Princeton, NJ 08543, USA.
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22
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Lewis MJ, Rada P, Johnson DF, Avena NM, Leibowitz SF, Hoebel BG. Galanin and alcohol dependence: neurobehavioral research. Neuropeptides 2005; 39:317-21. [PMID: 15885773 DOI: 10.1016/j.npep.2004.12.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Accepted: 12/17/2004] [Indexed: 10/25/2022]
Abstract
It is known that microinjection of galanin (GAL) intraventricularly or in specific hypothalamic sites increases food consumption and, conversely, the intake of food increases the expression of GAL in hypothalamic sites. Ethanol (EtOH) is a calorie-rich food as well as a drug of abuse. The research reviewed here shows that GAL may play a similar role in alcohol intake. First, experiments in which GAL was microinjected into the third ventricle or the paraventricular nucleus (PVN) showed increases in EtOH consumption. The increase in EtOH consumption occurred during both the light and dark cycles after GAL injection in the third ventricle in rats with limited EtOH access. Injection of GAL did not increase food intake in rats that had been chronically drinking alcohol. GAL receptor blockade reversed these increases. Microinjection of GAL directly into the PVN also increased ad libitum EtOH intake and blockade of these receptors in the PVN inhibited ad libitum EtOH consumption. Secondly, rats administered EtOH showed increases in GAL in the PVN and related hypothalamic sites. EtOH injection and voluntary intake, both ad libitum and limited access, increased GAL gene and peptide expression in the PVN consistently across administration procedures. These experiments show that GAL injection increases alcohol intake and that the intake of alcohol increases GAL, suggesting a positive feedback relationship between alcohol intake and specific hypothalamic GAL systems. Such a relationship may contribute to the motivation to consume excessive alcoholic beverages and the development of alcohol dependence.
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Affiliation(s)
- M J Lewis
- Department of Psychology, Princeton University, Green Hall, Princeton, NJ 08544, USA
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23
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Rada P, Avena NM, Hoebel BG. Daily bingeing on sugar repeatedly releases dopamine in the accumbens shell. Neuroscience 2005; 134:737-44. [PMID: 15987666 DOI: 10.1016/j.neuroscience.2005.04.043] [Citation(s) in RCA: 336] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2004] [Revised: 04/13/2005] [Accepted: 04/16/2005] [Indexed: 10/25/2022]
Abstract
Most drugs of abuse increase dopamine (DA) in the nucleus accumbens (NAc), and do so every time as a pharmacological response. Palatable food also releases accumbens-shell DA, but in naïve rats the effect can wane during a long meal and disappears with repetition. Under select dietary circumstances, sugar can have effects similar to a drug of abuse. Rats show signs of DA sensitization and opioid dependence when given intermittent access to sucrose, such as alterations in DA and mu-opioid receptors, cross-sensitization with amphetamine and alcohol, and behavioral and neurochemical signs of naloxone-precipitated withdrawal. The present experiment asks whether sucrose-dependent rats release DA each time they binge. We also predict that acetylcholine (ACh), which rises as the end of a meal, will be delayed in rats with intermittent access to sucrose. To create dependency, the experimental group (Daily Intermittent Sucrose) was maintained on a diet of 12-h food deprivation that extended 4 h into the dark, followed by 12-h access to a 10% sucrose solution and chow, daily, for 21 days. As the main result, these rats gradually increased their sucrose intake from 37 to 112 ml per day (from 13 to 20 ml in the first hour of access), and repeatedly increased extracellular DA to 130% of baseline as measured in the NAc shell by microdialysis during the first hour of sucrose access on day 1, day 2 and day 21. Three control groups failed to show a significant increase in extracellular DA on day 21: Sucrose only for 1 h on days 1 and 21 (Sucrose Twice), ad libitum access to sucrose and chow (Daily Ad libitum Sucrose), and intermittent chow instead of sucrose (Daily Intermittent Chow). Acetylcholine measured at the same time as DA, increased significantly toward the end and after each test meal in all groups. In the Daily Intermittent Sucrose group, the highest ACh levels (133%) occurred during the first sample after the sucrose meal ended. In summary, sucrose-dependent animals have a delayed ACh satiation response, drink more sucrose, and release more DA than sucrose- or binge-experienced, but non-dependent animals. These results suggest another neurochemical similarity between intermittent bingeing on sucrose and drugs of abuse: both can repeatedly increase extracellular DA in the NAc shell.
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Affiliation(s)
- P Rada
- Psychology Department, Green Hall, Princeton University, Princeton, NJ 08544, USA
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24
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Rada P, Johnson DF, Lewis MJ, Hoebel BG. In alcohol-treated rats, naloxone decreases extracellular dopamine and increases acetylcholine in the nucleus accumbens: evidence of opioid withdrawal. Pharmacol Biochem Behav 2004; 79:599-605. [PMID: 15582668 DOI: 10.1016/j.pbb.2004.09.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Accepted: 09/07/2004] [Indexed: 10/26/2022]
Abstract
Withdrawal from ethanol is aversive. The question is why. As with the withdrawal from morphine, nicotine, diazepam and sugar, the ethanol withdrawal state may involve an increase in nucleus accumbens (NAc) acetylcholine (ACh) causing an alteration of the dopamine (DA)-ACh balance in favor of ACh. Therefore the effects of acute and chronic alcohol (1 gm/kg/day i.p.) treatment on extracellular concentrations of NAc ACh and DA were determined before and after naloxone-precipitated withdrawal. Ethanol initially increased DA to 119% of baseline as measured by microdialysis. This was still the case on the 21st day of ethanol injection when DA increased to 126%. There was no effect of ethanol on ACh. However, naloxone (3 mg/kg s.c.) injected the next day decreased extracellular DA to 83% of baseline and caused a significant rise in ACh to 119%. This state of high ACh combined with low DA may contribute to the aversive aspects of alcohol withdrawal.
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Affiliation(s)
- P Rada
- Psychology Department, Princeton University, Princeton, NJ 08544, USA
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25
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Rada P, Moreno SA, Tucci S, Gonzalez LE, Harrison T, Chau DT, Hoebel BG, Hernandez L. Glutamate release in the nucleus accumbens is involved in behavioral depression during the PORSOLT swim test. Neuroscience 2003; 119:557-65. [PMID: 12770568 DOI: 10.1016/s0306-4522(03)00162-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An abnormality in glutamate function has been implicated in the neural substrate of depressive disorders. To investigate this in rats, the Porsolt swim test was used to assess the role of glutamate in the nucleus accumbens. Glutamate injected into the nucleus accumbens dose-dependently decreased swimming time on the test day (day 2), whereas N-methyl-D-aspartate antagonists dizocilpine and 2-amino-5-phosphonovalerate increased swimming, like an antidepressant. Dizocilpine injected before the conditioning trial (day 1) did not modify the swimming times during the first day but abolished behavioral depression on day 2. Microdialysis coupled to capillary-zone electrophoresis was then used to determine in vivo changes in glutamate release in 1-min samples during the swim test. On day 1, glutamate increased significantly and reached a maximum of 222% after 3 min of swimming. On day 2, baseline glutamate levels were back to normal, but when the animal was placed in the water, glutamate increased to 419% during the first minute, and the animals swam significantly less. For comparison, tail pinch on consecutive days was used as a nonspecific, repeated stressor while accumbens glutamate levels were measured. Tail pinch on the first day increased glutamate similar to the effect obtained during the first day of swimming; however, a second day of tail pinch decreased glutamate levels, instead of the potentiated response observed during the second day of swimming. These results show that accumbens glutamate plays a role in causing the behavioral aspects of depressed behavior as modeled in the swim test. The accumbens may be a potential site of action for drugs that alter behavioral depression.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, Universidad de los Andes, Mérida, Venezuela 5101-A
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26
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Colantuoni C, Schwenker J, McCarthy J, Rada P, Ladenheim B, Cadet JL, Schwartz GJ, Moran TH, Hoebel BG. Excessive sugar intake alters binding to dopamine and mu-opioid receptors in the brain. Neuroreport 2001; 12:3549-52. [PMID: 11733709 DOI: 10.1097/00001756-200111160-00035] [Citation(s) in RCA: 308] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Palatable food stimulates neural systems implicated in drug dependence; thus sugar might have effects like a drug of abuse. Rats were given 25% glucose solution with chow for 12 h followed by 12 h of food deprivation each day. They doubled their glucose intake in 10 days and developed a pattern of excessive intake in the first hour of daily access. After 30 days, receptor binding was compared to chow-fed controls. Dopamine D-1 receptor binding increased significantly in the accumbens core and shell. In contrast, D-2 binding decreased in the dorsal striatum. Binding to dopamine transporter increased in the midbrain. Opioid mu-1 receptor binding increased significantly in the cingulate cortex, hippocampus, locus coeruleus and accumbens shell. Thus, intermittent, excessive sugar intake sensitized D-1 and mu-1 receptors much like some drugs of abuse.
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Affiliation(s)
- C Colantuoni
- Department of Psychology, Green Hall, Princeton University, Princeton, NJ 08544, USA
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27
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Chau DT, Rada P, Kosloff RA, Taylor JL, Hoebel BG. Nucleus accumbens muscarinic receptors in the control of behavioral depression: antidepressant-like effects of local M1 antagonist in the Porsolt swim test. Neuroscience 2001; 104:791-8. [PMID: 11440810 DOI: 10.1016/s0306-4522(01)00133-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Systemically administered cholinomimetics or cholinesterase inhibitors can depress behavior in humans and animals, whereas antimuscarinic agents reverse this effect or even produce euphoria. Although these effects have been well documented, the specific brain regions that mediate them remain largely unknown. In the present experiments, muscarinic agonists and antagonists were locally injected into the nucleus accumbens of female Sprague-Dawley rats to test for their effects on behavioral depression in the Porsolt swim test and locomotor activity. Local, microinjections of the drugs in the accumbens elicited behaviors that were similar to the systemic effects reported in other studies. Injection of the non-specific agonist arecoline (40 and 80 microg) dose-dependently inhibited swimming and escape behavior. This may be mediated in part by accumbens M1 receptors because blocking these receptors with the specific antagonist pirenzepine (17.5 and 35.0 microg) did the opposite by increasing swimming. Gallamine (0.13, 0.44, and 0.88 microg), an antagonist at M2 receptors, dose-dependently decreased swimming. Two-way microdialysis suggested that this was in part due to the release of ACh by blocking M2 autoreceptors. Scopolamine, a mixed M1/M2 receptor antagonist, also released ACh but did not decrease swimming, probably because the M1 receptors were blocked; the drug (1.0 microg) increased swimming time, much like pirenzepine. With the exception of arecoline, none of the drugs significantly affected locomotor activity in a photocell cage. Arecoline (40 microg), which had decreased swimming, reduced activity. The present study suggests that muscarinic receptors in the nucleus accumbens can control immobility in the Porsolt swim test. The onset of immobility may depend on the activation of post-synaptic M1 receptors.
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Affiliation(s)
- D T Chau
- Psychology Department, Princeton University, Princeton, NJ 08544, USA
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28
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Rada P, Jensen K, Hoebel BG. Effects of nicotine and mecamylamine-induced withdrawal on extracellular dopamine and acetylcholine in the rat nucleus accumbens. Psychopharmacology (Berl) 2001; 157:105-10. [PMID: 11512050 DOI: 10.1007/s002130100781] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2000] [Accepted: 03/20/2001] [Indexed: 11/25/2022]
Abstract
RATIONALE Prior research suggests that high levels of acetylcholine (ACh) in the nucleus accumbens (NAc) are associated with aversive states such as morphine withdrawal, but this has not been tested for nicotine withdrawal. OBJECTIVES The goal was to test the hypothesis that acute nicotine decreases extracellular ACh and increases extracellular dopamine (DA) in the NAc, while withdrawal from nicotine causes an opposite neurochemical imbalance with high extracellular ACh and low DA. METHODS Rats were prepared with a microdialysis probe in the NAc (primarily the shell region). They received one injection of nicotine (0.5 mg/kg, s.c.) or chronic nicotine (9 mg/kg per day via osmotic minipump). RESULTS Naive animals receiving acute nicotine showed a mild, significant increase in both ACh (122% of baseline) and DA (124%). After chronic nicotine administration for 7 days, the nicotinic antagonist mecamylamine (1.0 mg/kg, s.c.) precipitated withdrawal with the appearance of somatic signs (teeth chattering and shakes/tremors) and a significant increase in extracellular ACh to 125% of baseline, while extracellular DA decreased to 65%. Control groups receiving saline in place of nicotine or mecamylamine did not show these effects. CONCLUSIONS Earlier work suggests that the observed release of accumbens ACh and DA in response to acute nicotine administration may be a factor in nicotine-induced suppression of appetite. ACh release during withdrawal, coupled with the decrease in extracellular DA may play a role in the aversive aspects of nicotine withdrawal that contribute to dependency.
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Affiliation(s)
- P Rada
- Department of Psychology, Princeton University, Princeton, NJ 08544, USA
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29
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Abstract
Medial prefrontal cortex (MPFC) transection enhances social interaction in an open arena test. Social interaction enhances dopaminergic activity in the nucleus accumbens (NAC). In the present set of experiments, microdialysis probes were implanted in the NAC, and glutamate, gamma-aminobutyric acid (GABA) and dopamine (DA) were measured during electrical stimulation of the MPFC, after coronal transection caudal to the MPFC and after a systemic injection of amphetamine in transected rats. Electrical stimulation of the MPFC caused a transient enhancement of glutamate release in the NAC, no change in GABA levels and a long lasting increase in DA levels. Medial prefrontal transection did not change basal glutamate or GABA levels in the NAC, but increased basal DA levels. Amphetamine administration decreased GABA levels in medial prefrontal transected rats, had no effect on glutamate and increased DA levels more than in controls. The experiments suggest that glutamatergic activity in the accumbens decreases dopamine release. Medial prefrontal transection reduces glutamatergic tone and enhances dopamine release, which probably decreases GABAergic activity in the NAC. Presumably, GABA inhibition in the NAC enhances social interaction.
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Affiliation(s)
- S Tucci
- Laboratory of Behavioral Physiology, Department of Physiology, School of Medicine, Los Andes University, Mérida, Venezuela.
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30
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Pérez J, Colasante C, Tucci S, Hernández L, Rada P. Effects of feeding on extracellular levels of glutamate in the medial and lateral portion of the globus pallidus of freely moving rats. Brain Res 2000; 877:91-4. [PMID: 10980248 DOI: 10.1016/s0006-8993(00)02658-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The globus pallidus (GP) is considered to be part of the basal ganglia and previous research has determined that it might be involved in feeding behavior. For example, it has been shown that the GP becomes active during feeding and that disinhibition of this nucleus, by locally injecting a GABA antagonist, is sufficient to induce feeding in a satiated rat. However, few studies have measured extracellular levels of glutamate during free feeding in the GP of rats. For this reason brain microdialysis coupled to capillary electrophoresis with laser-induced fluorescence was used to determine FTC-glutamate levels, either in the medial or lateral portion of the GP, of freely moving rats. Retrograde labeling of the neurons projecting to the two areas was also examined in an attempt to gain some insight on the identity of the neurons that released glutamate in the GP during feeding. Extracellular levels of glutamate-FTC differentially increased in both portions of the GP during a 2-min interval of free feeding. Retrograde labeling also showed that both areas received projections from different brain areas suggesting that each of the GP portions could be involved in separate aspects of the feeding behavior.
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Affiliation(s)
- J Pérez
- Laboratory of Behavioral Physiology, School of Medicine, University of Los Andes, 5101-A, Mérida, Venezuela
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31
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Abstract
Pharmacological, neurochemical, and behavioral techniques were used to characterize DA-ACh interaction within the lateral hypothalamus (LH) in the context of locomotion, feeding behavior, and reinforcement. In Experiment 1, the muscarinic agonist carbachol injected in the LH increased locomotor activity in proportion to dose. In Experiment 2, the same doses of carbachol proportionately increased exctracellular DA in the nucleus accumbens (Nac) as monitored by brain microdialysis. Dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) also increased. In Experiment 3, LH infusion by reverse microdialysis of the D(2) receptor blocker sulpiride released ACh in the LH in a dose-response manner. This suggested that sulpiride disinhibits ACh release via D(2) receptors in the LH and thereby facilitates behavior. Confirming this in Experiment 4, local LH atropine 5 min before sulpiride suppressed the locomotor response to sulpiride for about 20 min. These results suggest that sulpiride acts in the LH by disinhibiting a hypothalamic locomotor mechanism that is cholinergically driven and connected with the mesoaccumbens dopamine pathway. Given prior results that local sulpiride in the LH can induce hyperphagia and reward, this system may be involved in searching for food and rewarding feeding behavior. In conclusion, DA acts in the LH via D(2) receptors to inhibit cholinergic neurons or terminals that are part of an approach system for eating.
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Affiliation(s)
- M P De Parada
- Los Andes University, Department of Physiology, School of Medicine, 5101-A, Mérida, Venezuela
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32
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Páez X, Rada P, Hernández L. Neutral amino acids monitoring in phenylketonuric plasma microdialysates using micellar electrokinetic chromatography and laser-induced fluorescence detection. J Chromatogr B Biomed Sci Appl 2000; 739:247-54. [PMID: 10755369 DOI: 10.1016/s0378-4347(99)00536-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Neutral and non-polar amino acids such as phenylalanine (Phe), valine (Val), tyrosine (Tyr), threonine (Thre) and GABA are hard to resolve by capillary zone electrophoresis (CZE). Their separation is possible by adding a surfactant to the mobile phase. This method is called micellar electrokinetic chromatography (MEKC). We used MEKC with laser-induced fluorescence detection (LIFD) to separate and quantitate these amino acids in plasma microdialysates of patients with phenylketonuria (PKU). This disease is an inborn enzymatic defect with decreased conversion of Phe to Tyr that causes severe neurological damage and mental deterioration, which is diagnosed by measuring plasma Phe and Phe/Tyr ratio. The amino acids tested had linear concentration-signal relation. PKU patients had significantly higher Phe, lower Tyr, 21 times higher Phe/Tyr ratio and decreased values of Val and Thre than controls. These results show that microdialysis of biological fluids coupled with MEKC-LIFD is a convenient technique to measure neutral amino acids in clinical disorders such as PKU.
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Affiliation(s)
- X Páez
- Laboratory of Behavioral Physiology, School of Medicine, Universidad de los Andes, Mérida, Venezuela.
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33
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Paredes D, Rada P, Bonilla E, Gonzalez LE, Parada M, Hernandez L. Melatonin acts on the nucleus accumbens to increase acetylcholine release and modify the motor activity pattern of rats. Brain Res 1999; 850:14-20. [PMID: 10629744 DOI: 10.1016/s0006-8993(99)01992-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Brain microdialysis coupled to high performance liquid chromatography with electrochemical detection (HPLC-ED) was used to evaluate the influence of melatonin on extracellular concentration of acetylcholine (ACh) in the nucleus accumbens (NAc) of rats. Motor activity was simultaneously monitored during the dialysis sessions with an activity meter. Melatonin and prazosin were administered locally through the dialysis probe. It was found that melatonin dose-dependently increased accumbens ACh. Melatonin (3 microM) decreased horizontal activity and increased vertical activity, while another dose (100 microM) enhanced both horizontal and vertical activity. Prazosin, a putative melatonin antagonist, blocked the effects of melatonin on both motor activity and ACh release when given 20 min before melatonin. Overall, these results suggest that melatonin modulates the release of ACh in the NAc and the pattern of motor activity in the rat.
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Affiliation(s)
- D Paredes
- Instituto de Investigaciones Clínicas, Facultad de Medicina, La Universidad del Zulia, Maracaibo, Venezuela
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34
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Rada P, Tucci S, Teneud L, Paez X, Perez J, Alba G, García Y, Sacchettoni S, del Corral J, Hernandez L. Monitoring gamma-aminobutyric acid in human brain and plasma microdialysates using micellar electrokinetic chromatography and laser-induced fluorescence detection. J Chromatogr B Biomed Sci Appl 1999; 735:1-10. [PMID: 10630884 DOI: 10.1016/s0378-4347(99)00386-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to its low electrophoretic mobility, few studies have been able to measure gamma aminobutyric acid (GABA) in biological samples by means of capillary zone electrophoresis. Nevertheless, in micellar electrokinetic chromatography (MEKC) by adding a surfactant to the mobile phase separation can be carried out on the basis of the partition coefficient of the molecules rather than their electrophoretic mobility. In the present study microdialysis coupled to MEKC with laser induced fluorescence detection was used to successfully monitor GABA from cerebrospinal fluid and plasma dialysates. Moreover, we monitored changes in extracellular GABA from a human brain. Microdialysis samples were collected from a Parkinson's disease patient undergoing a thallamotomy as part of her treatment. Significant decreases in extracellular GABA were detected during high frequency electrical stimulation and following a thermolesion of the thalamus. These results demonstrate the feasibility of MEKC coupled to laser-induced fluorescence detection in resolving neutral amino acids, specifically GABA, from different human body fluids.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, School of Medicine, University of Los Andes, Merida, Venezuela
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35
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Abstract
The role of glutamate in conditioned taste aversion was investigated. Both, in the amygdala (AMYG) and in the lateral hypothalamus (LH) extracellular levels of glutamate were assessed by microdialysis and capillary electrophoresis with laser induced fluorescence detection. Rats were conditioned by pairing a novel flavor (strawberry flavor) with an intraperitoneal injection of lithium chloride. When the conditioned stimulus (strawberry flavored solution) was injected into the mouth of conditioned rats, there was an increase of glutamate release in the AMYG, and a decrease in glutamate release in the LH. These results predicted that glutamate release in the AMYG and the LH was involved in CTA. This possibility was tested by MK-801 (glutamate antagonist) and glutamate microinjections. MK-801 injections in AMYG attenuated the rejection of the novel flavor, and in the LH did not cause any effect on CTA. Glutamate microinjections in the AMYG caused CTA. These results suggest that glutamatergic activity in the AMYG might be a relevant neurochemical correlate and cause of conditioned taste aversion.
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Affiliation(s)
- S Tucci
- Laboratory of Behavioral Physiology, Department of Physiology, School of Medicine, Los Andes University, Apartado de correos 109, 5101-A, Mérida, Venezuela.
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36
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Rada P, Tucci S, Pérez J, Teneud L, Chuecos S, Hernández L. In vivo monitoring of gabapentin in rats: a microdialysis study coupled to capillary electrophoresis and laser-induced fluorescence detection. Electrophoresis 1998; 19:2976-80. [PMID: 9870398 DOI: 10.1002/elps.1150191629] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gabapentin (GP) is a new anticonvulsant used in refractory epilepsy. Few studies have monitored the drug in vivo. We report the combination of capillary electrophoresis and laser-induced fluorescence detection (CZE-LIFD) with brain microdialysis and plasma ultrafiltration in an attempt to measure GP and offer an alternative technique for pharmacokinetic studies. We found that CZE-LIFD is capable of linearly measuring 10(-7)-10(-9) M GP in a 1 nL volume. It was also demonstrated that it is possible to monitor GP in prefrontal cortex dialysates and plasma in rats. It is concluded that the method permits in vivo monitoring of the drug in pharmacological as well as in clinical studies.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, University of Los Andes, Mérida, Venezuela.
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37
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Rada P, Mark GP, Hoebel BG. Galanin in the hypothalamus raises dopamine and lowers acetylcholine release in the nucleus accumbens: a possible mechanism for hypothalamic initiation of feeding behavior. Brain Res 1998; 798:1-6. [PMID: 9666056 DOI: 10.1016/s0006-8993(98)00315-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rats were prepared with two implanted guide shafts, one for microdialysis to measure extracellular dopamine (DA) and acetylcholine (ACh) in the posterior, medial nucleus accumbens (NAc), and the other for microinjection of galanin, neuropeptide Y or saline in the hypothalamic paraventricular nucleus (PVN). There was an increase in DA release and a decrease in ACh in the NAc following microinjections of galanin into the PVN. The effect was observed only in rats for which identical galanin injections induced feeding in separate tests. Ringer injections had no effects. Unlike galanin, neuropeptide Y in the PVN induced eating without altering DA/ACh; whereas earlier results showed that norepinephrine in the PVN works like galanin. These results suggest that galanin initiates feeding, in part, by activating the mesolimbic DA system and suppressing intrinsic cholinergic activity in the NAc. This may prime instrumental behavior with DA while disinhibiting behavior by lowering ACh.
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Affiliation(s)
- P Rada
- Department of Psychology, Princeton University, Princeton, NJ, 08544-1010, USA
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38
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Sepulveda MJ, Hernandez L, Rada P, Tucci S, Contreras E. Effect of precipitated withdrawal on extracellular glutamate and aspartate in the nucleus accumbens of chronically morphine-treated rats: an in vivo microdialysis study. Pharmacol Biochem Behav 1998; 60:255-62. [PMID: 9610950 DOI: 10.1016/s0091-3057(97)00550-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Excitatory amino acids release during morphine or naloxone administration was studied in rats. Microdialysis in freely moving animals and capillary electrophoresis with laser-induced fluorescence detection were used to measure several amino acids including glutamate and aspartate in the extracellular fluid at the nucleus accumbens. Perfusion with a calcium-free Ringer's solution decreased glutamate and aspartate in nucleus accumbens dialysates to 35% of its baseline levels, suggesting partial synaptic origin of these amino acids. The first morphine injection decreased glutamate and aspartate to 50% of its baseline level. After repeated morphine injections this effect disappeared, suggesting tolerance. Naloxone injections to morphine-dependent rats increased 300% glutamate and aspartate release; these experiments suggest that excitatory amino acid release in the nucleus accumbens might play a role in morphine withdrawal.
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Affiliation(s)
- M J Sepulveda
- Department of Physiology, Medical School, Los Andes University, Merida, Venezuela
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39
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Baptista T, Araujo H, Rada P, Hernández L. Congenital neuroblastoma in a boy born to a woman with bipolar disorder treated with carbamazepine during pregnancy. Prog Neuropsychopharmacol Biol Psychiatry 1998; 22:445-54. [PMID: 9612842 DOI: 10.1016/s0278-5846(98)00016-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
1. A metastatic neuroblastoma was detected immediately after birth in a boy born to a 26 year old woman with bipolar disorder, who received carbamazepine (400 mg/day) all through her pregnancy. The primary tumor was probably located in the adrenal gland of the right side, and multiple metastatic lesions were detected in the skin. 2. In this report the authors review the literature about the side effects teratogenic and carcinogenic effects of carbamazepine, the epidemiology and evolution of the neuroblastoma, and the current scientific opinion about the pharmacological treatment of the pregnant with mood disorders. 3. A causal relationship between the use of carbamazepine and the neuroblastoma development in the present case can not be established; however, as the carcinogenic and teratogenic effects of the drug have been basically assessed in epileptic women, our aim is to alert the medical community in order to conduct further research in psychiatric patients.
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Affiliation(s)
- T Baptista
- Department of Physiology, Medical School, Universidad de los Andes, Mérida, Venezuela
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40
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Tucci S, Pinto C, Goyo J, Rada P, Hernández L. Measurement of glutamine and glutamate by capillary electrophoresis and laser induced fluorescence detection in cerebrospinal fluid of meningitis sick children. Clin Biochem 1998; 31:143-50. [PMID: 9629487 DOI: 10.1016/s0009-9120(98)00003-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Cerebrospinal fluid glutamine and glutamate concentrations were measured by CZE-LIFD in normal and meningitis sick children. DESIGN AND METHODS A derivatization procedure for glutamine was optimized using CZE-LIFD. Cytochemical and bacteriological analysis were made to 152 CSF from children suspicious of suffering meningitis. RESULTS CSF-glutamine concentration was lower in children with viral and bacterial meningitis. In addition, the group infected with Haemophilus influenzae had the lowest concentrations. By contrast, glutamate concentration was higher in children with meningitis. Glutamine concentration increased as the clinical condition of the patient improved. CONCLUSIONS Lower concentrations of glutamine in children with bacterial meningitis might be due to the use of this amino acid for bacterial growth while higher concentrations of glutamate might be due to cell destruction. The results indicate that CZE-LIFD is an alternative tool for the determination of amino acids in CSF.
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Affiliation(s)
- S Tucci
- Department of Physiology, Medical School, Los Andes University, Mérida, Venezuela.
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41
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Rada P, Tucci S, Murzi E, Hernández L. Extracellular glutamate increases in the lateral hypothalamus and decreases in the nucleus accumbens during feeding. Brain Res 1997; 768:338-40. [PMID: 9369334 DOI: 10.1016/s0006-8993(97)00788-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glutamate release was monitored in the lateral hypothalamus and the nucleus accumbens during a meal using 30 s resolution microdialysis and capillary zone electrophoresis with laser-induced fluorescence. A significant increase in hypothalamic glutamate and a decrease in accumbens glutamate were observed. These results, added to previous pharmacological studies, suggest that glutamatergic synapses in the lateral hypothalamus and the nucleus accumbens might be involved in the control of feeding behavior.
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Affiliation(s)
- P Rada
- Laboratory of Behavioral Physiology, School of Medicine, University of Los Andes, Mérida, Venezuela
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42
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Guzman NA, Park SS, Schaufelberger D, Hernandez L, Paez X, Rada P, Tomlinson AJ, Naylor S. New approaches in clinical chemistry: on-line analyte concentration and microreaction capillary electrophoresis for the determination of drugs, metabolic intermediates, and biopolymers in biological fluids. J Chromatogr B Biomed Sci Appl 1997; 697:37-66. [PMID: 9342656 DOI: 10.1016/s0378-4347(97)00275-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The use of capillary electrophoresis (CE) for clinically relevant assays is attractive since it often presents many advantages over contemporary methods. The small-diameter tubing that holds the separation medium has led to the development of multicapillary instruments, and simultaneous sample analysis. Furthermore, CE is compatible with a wide range of detectors, including UV-Vis, fluorescence, laser-induced fluorescence, electrochemistry, mass spectrometry, radiometric, and more recently nuclear magnetic resonance, and laser-induced circular dichroism systems. Selection of an appropriate detector can yield highly specific analyte detection with good mass sensitivity. Another attractive feature of CE is the low consumption of sample and reagents. However, it is paradoxical that this advantage also leads to severe limitation, namely poor concentration sensitivity. Often high analyte concentrations are required in order to have injection of sufficient material for detection. In this regard, a series of devices that are broadly termed 'analyte concentrators' have been developed for analyte preconcentration on-line with the CE capillary. These devices have been used primarily for non-specific analyte preconcentration using packing material of the C18 type. Alternatively, the use of very specific antibody-containing cartridges and enzyme-immobilized microreactors have been demonstrated. In the current report, we review the likely impact of the technology of capillary electrophoresis and the role of the CE analyte concentrator-microreactor on the analysis of biomolecules, present on complex matrices, in a clinical laboratory. Specific examples of the direct analysis of physiologically-derived fluids and microdialysates are presented, and a personal view of the future of CE in the clinical environment is given.
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Affiliation(s)
- N A Guzman
- R. W. Johnson Pharmaceutical Research Institute, Raritan, NJ 08869, USA
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43
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Tucci S, Rada P, Sepúlveda MJ, Hernandez L. Glutamate measured by 6-s resolution brain microdialysis: capillary electrophoretic and laser-induced fluorescence detection application. J Chromatogr B Biomed Sci Appl 1997; 694:343-9. [PMID: 9252048 DOI: 10.1016/s0378-4347(96)00488-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the present experiment the combination of brain microdialysis and CZE-LIFD permitted the measurement of glutamate in 100 nl microdialysis samples collected every 5 or 6 s. Samples were collected every 6 s, in rats anesthetized with two different anesthetic agents (ketamine and sodium thiopental). A microdialysis probe was inserted in the cortex of an anesthetized rat in the territory irrigated by the middle cerebral artery. The artery was clamped for 30 s and then released. The samples were derivatized with fluorescein isothiocyanate I (FITC) by means of a continuous-flow reactor, collected and injected into a home-made CZE-LIFD instrument. Glutamate decreased immediately after clamping the artery in ketamine anesthetized rats and increased 1 min after the onset of the ischemia in sodium thiopental anesthetized rats. In another experiment a 60 mM KCl solution was injected through a microdialysis probe inserted in the hippocampus of an anesthetized rat. In the first 5 s after the KCl solution reached the tissue, glutamate increased but gamma-aminobutytic acid and glutamine did not. The experiments show that time resolution of brain microdialysis can be reduced to a few seconds if the analytical technique is the proper one.
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Affiliation(s)
- S Tucci
- Department of Physiology, Los Andes University, Merida, Venezuela
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44
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Parada MA, Hernandez L, Puig de Parada M, Rada P, Murzi E. Selective action of acute systemic clozapine on acetylcholine release in the rat prefrontal cortex by reference to the nucleus accumbens and striatum. J Pharmacol Exp Ther 1997; 281:582-8. [PMID: 9103547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The effects of i.p. clozapine [0 (n = 6), 5 (n = 5), 10 (n = 5), 20 (n = 9) and 40 (n = 5) mg/kg] on acetylcholine (ACh) release in the prefrontal cortex (PFC), nucleus accumbens (NAC) and striatum (STR) were studied by simultaneous triple microdialysis in freely moving rats. Clozapine dose-responsively increased extracellular ACh in the studied areas. The effect was larger in the PFC. Comparisons of the slopes of the regression equations showed differences between the effects in PFC and nucleus accumbens (t = 4.29; df = 56; P < .001) and PFC and STR (t = 4.56), but not between nucleus accumbens and STR. These differential actions were not artifacts of the simultaneous perfusion because clozapine (20 mg/kg) increased ACh levels during single microdialysis of the PFC (353 +/- 72%; n = 5) or STR (168 +/- 24%; n = 5), in the same proportion as the respective increases in those areas during the simultaneous triple microdialysis (PFC = 330 +/- 41%; STR = 144 +/- 18%; n = 9). Local infusion of tetrodotoxin (10 microM) reduced ACh in the areas studied to about 30% of the mean baselines, confirming the neuronal origin of this neurotransmitter. Extrapolation of these results to humans suggests that adequate levels of cholinergic activity in the PFC are required for mental health, and that a similar ACh release in the human PFC by clozapine could be therapeutic. The low impact on striatal ACh could explain the lack of extrapyramidal symptoms by clozapine.
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Affiliation(s)
- M A Parada
- Los Andes University, Department of Physiology, School of Medicine, Mérida, Venezuela
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45
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Murzi E, Rada P, Puig de Parada M, Parada MA, Valecillos B, Tilac CA, Hernandez L. Atropine decreases drinking but not feeding and induces less hypothalamic acetylcholine release in diabetic rats. Brain Res 1997; 752:184-8. [PMID: 9106455 DOI: 10.1016/s0006-8993(96)01442-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Drinking, feeding and hypothalamic extracellular acetylcholine (ACh) release was measured before and after the administration of several doses of atropine sulfate in streptozotocin (STZ)-diabetic and normal rats. Drinking but not feeding was dose-relatedly decreased by i.p. or intrahypothalamic injections of atropine in STZ-diabetic rats. Hypothalamic ACh release, as measured by microdialysis, increased less (dose-related) in diabetic than normal rats following an i.p. administration of atropine. Ach basal levels were the same in both groups. These results are discussed in terms of a hyperactive hypothalamic cholinergic (muscarinic) system involved in the diabetic polydipsia.
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Affiliation(s)
- E Murzi
- Laboratory of Behavioral Physiology, School of Medicine, Los Andes University, Mérida, Venezuela
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46
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Abstract
Prefrontal cortex microdialysis was done in rats that had received intraperitoneal amphetamine (AMPH). Samples were derivatized with 10(-4) M fluorescein isothiocyanate and incubated for 18 h. AMPH was separated by capillary electrophoresis (CE) and detected by laser-induced fluorescence detection (LIFD) from 30 to 150 min after injection. The limit of mass detection was 3 amol, which is three orders of magnitude lower than that in gas chromatography-mass spectrometry, and the limit of concentration detection was 3 x 10(-9) M. The results showed that CE-LIFD is a good method for detecting AMPH in brain dialysates of rats.
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Affiliation(s)
- X Páez
- Department of Physiology, School of Medicine, Universidad de los Andes, Mérida, Venezuela
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47
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Jones AP, Pothos EN, Rada P, Olster DH, Hoebel BG. Maternal hormonal manipulations in rats cause obesity and increase medial hypothalamic norepinephrine release in male offspring. Brain Res Dev Brain Res 1995; 88:127-31. [PMID: 8665659 DOI: 10.1016/0165-3806(95)00078-r] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In previous work it has been shown that adult male, but not female, offspring of rats that have either been injected with Protamine Zinc Insulin on days 15-20 gestation, or undernourished during the first 2 weeks of gestation, develop significant obesity commencing at about 50 days of age. The present experiment examines the question of whether rats with these two forms of obesity display neurochemical abnormalities in areas of the brain known to influence food intake and body weight. Twenty-one gauge stainless steel guide shafts were surgically implanted using standard stereotaxic procedures. One week later 26 ga microdialysis probes were lowered into the medial hypothalamus. Dialysates collected from male offspring in the two experimental conditions contain significantly higher norepinephrine (NE) levels than did controls. It would appear that in addition to sharing a similar time course of onset and a sex dependent expression of obesity, both of these models are also characterized by elevated medial hypothalamic NE. Since this obesity appears only in males, and at a time when testosterone levels are rapidly rising in males, and since testosterone has been shown to elevate food intake and body weights in rats, we also investigated whether gonadal weights or circulating testosterone levels were differentially elevated by our manipulations.
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Affiliation(s)
- A P Jones
- Pitzer College, Claremont, CA 91711, USA
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48
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Parada MA, de Parada MP, Rada P, Hernandez L. Sulpiride increases and dopamine decreases intracranial temperature in rats when injected in the lateral hypothalamus: an animal model for the neuroleptic malignant syndrome? Brain Res 1995; 674:117-21. [PMID: 7773679 DOI: 10.1016/0006-8993(94)01455-q] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Sulpiride in the perifornical lateral hypothalamus (pfLH) (4, 8 and 16 micrograms/0.5 microliter) increased intracranial temperature (Tic). The hyperthermia started immediately after the injection, peaked 30 min later and lasted for more than 90 min. Sulpiride (12 micrograms) accelerated recovery from hypothermia in anesthetized animals. Forty-five min after sulpiride Tic raised 1.17 +/- 0.06 degrees C. After a control injection the raise was only 0.5 +/- 0.13 degrees C. Locally applied dopamine (DA) (5, 10 and 20 micrograms) 5 min before sulpiride (12 micrograms) attenuated sulpiride hyperthermia. The largest DA dose reduced Tic (-1.21 degrees C) when administered alone. These findings suggest the existence of D2 receptors in the LH involved in thermoregulation. Changes are that D2 receptors in the human LH could be responsible for the neuroleptic malignant syndrome (NMS), and that sulpiride injections in the rat LH could be used as a model for the study of the pathogenesis of this syndrome.
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Affiliation(s)
- M A Parada
- Los Andes University, Department of Physiology, School of Medicine, Venezuela
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49
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Affiliation(s)
- B G Hoebel
- Department of Psychology, Princeton University, New Jersey 08540
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50
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Abstract
A flexible intravenous microdialysis probe was constructed from Silastic tubing (0.5 mm ID and 1.0 mm OD), with a cellulose hollow fiber tip 0.2 mm in diameter and 25 mm long with a 6,000 mol wt cut off. In vitro tests showed relative recovery rates of 39.1 +/- 1.9% for epinephrine. In vivo tests in freely moving rats, 36 h and 7 days after surgery, showed stable amounts of epinephrine and glucose. After intraperitoneal injections of 2-deoxy-D-glucose, circulating levels of epinephrine and glucose increased significantly. Similar results were obtained several days after implantation of the probe. We conclude that in situations where prolonged blood sampling is necessary, the flexible microdialysis probe provides a reliable means of accessing circulating levels of neuroactive compounds, nutrients, metabolites, and drugs.
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Affiliation(s)
- P Rada
- Laboratorio de Fisiologia de la Conducta, Escuela de Medicina, Universidad de los Andes, Mérida, Venezuela
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