{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T20:47:44Z","timestamp":1778186864577,"version":"3.51.4"},"reference-count":42,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2018,1,23]],"date-time":"2018-01-23T00:00:00Z","timestamp":1516665600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>2-Methyl-6-(phenylethynyl)pyridine (MPEP), a negative allosteric modulator of the metabotropic glutamate receptor (mGluR) 5, protects hepatocytes from ischemic injury. In astrocytes and microglia, MPEP depletes ATP. These findings seem to be self-contradictory, since ATP depletion is a fundamental stressor in ischemia. This study attempted to reconstruct the mechanism of MPEP-mediated ATP depletion and the consequences of ATP depletion on protection against ischemic injury. We compared the effects of MPEP and other mGluR5 negative modulators on ATP concentration when measured in rat hepatocytes and acellular solutions. We also evaluated the effects of mGluR5 blockade on viability in rat hepatocytes exposed to hypoxia. Furthermore, we studied the effects of MPEP treatment on mouse livers subjected to cold ischemia and warm ischemia reperfusion. We found that MPEP and 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) deplete ATP in hepatocytes and acellular solutions, unlike fenobam. This finding suggests that mGluR5s may not be involved, contrary to previous reports. MPEP, as well as MTEP and fenobam, improved hypoxic hepatocyte viability, suggesting that protection against ischemic injury is independent of ATP depletion. Significantly, MPEP protected mouse livers in two different ex vivo models of ischemia reperfusion injury, suggesting its possible protective deployment in the treatment of hepatic inflammatory conditions.<\/jats:p>","DOI":"10.3390\/ijms19020314","type":"journal-article","created":{"date-parts":[[2018,1,23]],"date-time":"2018-01-23T13:06:51Z","timestamp":1516712811000},"page":"314","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Selective Blockade of the Metabotropic Glutamate Receptor mGluR5 Protects Mouse Livers in In Vitro and Ex Vivo Models of Ischemia Reperfusion Injury"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2337-2897","authenticated-orcid":false,"given":"Andrea","family":"Ferrigno","sequence":"first","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Clarissa","family":"Berardo","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laura","family":"Di Pasqua","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Veronica","family":"Siciliano","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Plinio","family":"Richelmi","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ferdinando","family":"Nicoletti","sequence":"additional","affiliation":[{"name":"Department of Physiology and Pharmacology, Sapienza University, 00185 Roma, Italy"},{"name":"I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2464-6127","authenticated-orcid":false,"given":"Mariapia","family":"Vairetti","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Therapeutics, Cellular and Molecular Pharmacology and Toxicology Unit, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,1,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2097","DOI":"10.3390\/molecules16032097","article-title":"Positive allosteric modulators of type 5 metabotropic glutamate receptors (mGluR5) and their therapeutic potential for the treatment of CNS disorders","volume":"16","author":"Cleva","year":"2011","journal-title":"Molecules"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1017","DOI":"10.1016\/j.neuropharm.2010.10.022","article-title":"Metabotropic glutamate receptors: From the workbench to the bedside","volume":"60","author":"Nicoletti","year":"2011","journal-title":"Neuropharmacology"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Durand, D., Carniglia, L., Caruso, C., and Lasag, M. (2011). Metabotropic Glutamate Receptors in Peripheral Tissues: Implications for Toxicology. Anxiety Disorders, InTech.","DOI":"10.5772\/19802"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1234","DOI":"10.1124\/mol.105.018390","article-title":"Insulin secretion is controlled by mGlu5 metabotropic glutamate receptors","volume":"69","author":"Storto","year":"2006","journal-title":"Mol. Pharmacol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1002\/hep.510310315","article-title":"Selective blockade of mGlu5 metabotropic glutamate receptors protects rat hepatocytes against hypoxic damage","volume":"31","author":"Storto","year":"2000","journal-title":"Hepatology"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1254\/jphs.09R16FM","article-title":"New frontiers in gut nutrient sensor research: luminal glutamate-sensing cells in rat gastric mucosa","volume":"112","author":"Nakamura","year":"2010","journal-title":"J. Pharmacol. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1677\/joe.0.1700071","article-title":"Expression of metabotropic glutamate receptors in the rat and human testis","volume":"170","author":"Storto","year":"2001","journal-title":"J. Endocrinol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1177\/0192623308315663","article-title":"Neuroexcitatory targets in the female reproductive system of the nonhuman primate (Macaca fascicularis)","volume":"36","author":"Gill","year":"2008","journal-title":"Toxicol. Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Nicoletti, F., Battaglia, G., Storto, M., Ngomba, R.T., Iacovelli, L., Arcella, A., Gradini, R., Sale, P., Rampello, L., and De Vita, T. (2007). Metabotropic glutamate receptors: Beyond the regulation of synaptic transmission. Psychoneuroendocrinology, 32.","DOI":"10.1016\/j.psyneuen.2007.04.015"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"R1","DOI":"10.1016\/S0014-2999(97)81950-4","article-title":"Metabotropic glutamate receptor agonists stimulate polyphosphoinositide hydrolysis in primary cultures of rat hepatocytes","volume":"338","author":"Sureda","year":"1997","journal-title":"Eur. J. Pharmacol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.ejphar.2004.06.023","article-title":"Mouse hepatocytes lacking mGlu5 metabotropic glutamate receptors are less sensitive to hypoxic damage","volume":"497","author":"Storto","year":"2004","journal-title":"Eur. J. Pharmacol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1186\/s12974-014-0190-7","article-title":"Inhibition of metabotropic glutamate receptor 5 induces cellular stress through pertussis toxin-sensitive Gi-proteins in murine BV-2 microglia cells","volume":"11","author":"Chantong","year":"2014","journal-title":"J. Neuroinflamm."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e00132","DOI":"10.1042\/AN20130040","article-title":"Role of glycogenolysis in stimulation of ATP release from cultured mouse astrocytes by transmitters and high K+ concentrations","volume":"6","author":"Xu","year":"2014","journal-title":"ASN Neuro"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"63","DOI":"10.5812\/atr.12501","article-title":"Hepatic ischemia and reperfusion injury and trauma: Current concepts","volume":"2","author":"Papadopoulos","year":"2013","journal-title":"Arch. Trauma Res."},{"key":"ref_15","unstructured":"Ferrigno, A., Berardo, C., di Pasqua, L.G., Siciliano, V., and Vairetti, M. (2017). 100 microM DHPG Did Not Alter ATP Concentration When Added to Mitochondrial Suspensions or to Primary Rat Hepatocytes, Cellular and Molecular Pharmacology and Toxicology Unit, University Pavia, Pavia, Italy, unpublished work."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1002\/(SICI)1098-1136(199905)26:3<233::AID-GLIA5>3.0.CO;2-2","article-title":"A plethora of presynaptic proteins associated with ATP-storing organelles in cultured astrocytes","volume":"26","author":"Maienschein","year":"1999","journal-title":"Glia"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1124\/jpet.105.089839","article-title":"Fenobam: A Clinically validated nonbenzodiazepine anxiolytic is a potent, selective, and noncompetitive mGlu5 receptor antagonist with inverse agonist activity","volume":"315","author":"Porter","year":"2005","journal-title":"J. Pharmacol. Exp. Ther."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1002\/bip.20229","article-title":"Amino acid recognition by Venus flytrap domains is encoded in an 8-residue motif","volume":"80","author":"Acher","year":"2005","journal-title":"Biopolymers"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/s12975-013-0314-x","article-title":"Ionic regulation of cell volume changes and cell death after ischemic stroke","volume":"5","author":"Song","year":"2014","journal-title":"Transl. Stroke Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"91","DOI":"10.3389\/fncel.2015.00091","article-title":"Researching glutamate\u2014Induced cytotoxicity in different cell lines: A comparative\/collective analysis\/study","volume":"9","author":"Kritis","year":"2015","journal-title":"Front. Cell. Neurosci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1038\/383089a0","article-title":"Control of calcium oscillations by phosphorylation of metabotropic glutamate receptors","volume":"383","author":"Kawabata","year":"1996","journal-title":"Nature"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1261","DOI":"10.1002\/neu.480230915","article-title":"Excitotoxic cell death","volume":"23","author":"Choi","year":"1992","journal-title":"J. Neurobiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1016\/S0165-5728(00)00269-1","article-title":"Expression of metabotropic glutamate receptors in murine thymocytes and thymic stromal cells","volume":"109","author":"Storto","year":"2000","journal-title":"J. Neuroimmunol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"G809","DOI":"10.1152\/ajpgi.2001.281.3.G809","article-title":"Cold preservation-warm reoxygenation increases hepatocyte steady-state Ca2+ and response to Ca2+-mobilizing agonist","volume":"281","author":"Elimadi","year":"2001","journal-title":"Am. J. Physiol. Gastrointest. Liv. Physiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1258\/002367706777611460","article-title":"The isolated perfused rat liver: Standardization of a time-honoured model","volume":"40","author":"Bessems","year":"2006","journal-title":"Lab. Anim."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1016\/j.vascn.2012.10.001","article-title":"Troubleshooting and improving the mouse and rat isolated perfused liver preparation","volume":"67","author":"Ferrigno","year":"2013","journal-title":"J. Pharmacol. Toxicol. Methods"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1023\/B:ABME.0000019181.18194.51","article-title":"Hypothermic machine preservation in liver transplantation revisited: Concepts and criteria in the new millennium","volume":"32","author":"Verkerke","year":"2004","journal-title":"Ann. Biomed. Eng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"G15","DOI":"10.1152\/ajpgi.00342.2002","article-title":"Molecular mechanisms of hepatic ischemia-reperfusion injury and preconditioning","volume":"284","author":"Jaeschke","year":"2003","journal-title":"Am. J. Physiol. Gastrointest. Liv. Physiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1936","DOI":"10.1172\/JCI114656","article-title":"Role of tumor necrosis factor-alpha in the pathophysiologic alterations after hepatic ischemia\/reperfusion injury in the rat","volume":"85","author":"Colletti","year":"1990","journal-title":"J. Clin. Invest."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1097\/00024382-199809000-00006","article-title":"Tumor necrosis factor up-regulates intercellular adhesion molecule 1, which is important in the neutrophil-dependent lung and liver injury associated with hepatic ischemia and reperfusion in the rat","volume":"10","author":"Colletti","year":"1998","journal-title":"Shock"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"752","DOI":"10.1006\/bbrc.1996.0968","article-title":"Molecular cloning of the rat inducible nitric oxide synthase gene promoter","volume":"223","author":"Eberhardt","year":"1996","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/s11010-009-0259-2","article-title":"TNF-\u03b1 modulates iNOS expression in an experimental rat model of indomethacin-induced jejunoileitis","volume":"336","author":"Nandi","year":"2010","journal-title":"Mol. Cell. Biochem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"695","DOI":"10.1111\/1440-1681.12410","article-title":"Selective blockade of mGlu5 metabotropic glutamate receptors is protective against hepatic mitochondrial dysfunction in 6-OHDA lesioned Parkinsonian rats","volume":"42","author":"Ferrigno","year":"2015","journal-title":"Clin. Exp. Pharmacol. Physiol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1016\/j.bbadis.2011.11.008","article-title":"Impaired hepatic function and central dopaminergic denervation in a rodent model of Parkinson\u2019s disease: A self-perpetuating crosstalk?","volume":"1822","author":"Vairetti","year":"2012","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/S0021-9258(19)52451-6","article-title":"Protein measurement with the Folin phenol reagent","volume":"193","author":"Lowry","year":"1951","journal-title":"J. Biol. Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.ejphar.2004.05.042","article-title":"Protection by cyclosporin A of mitochondrial and cellular functions during a cold preservation-warm reperfusion of rat liver","volume":"495","author":"Plin","year":"2004","journal-title":"Eur. J. Pharmacol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/S0168-8278(02)00384-7","article-title":"Selective blockade of mGlu5 metabotropic glutamate receptors is protective against acetaminophen hepatotoxicity in mice","volume":"38","author":"Storto","year":"2003","journal-title":"J. Hepatol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1177\/039463201402700306","article-title":"Changes in extra- and intracellular pH in hepatocytes exposed to gabexate mesilate","volume":"27","author":"Imberti","year":"2014","journal-title":"Int. J. Immunopathol. Pharmacol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Ferrigno, A., Gregotti, C., Richelmi, P., and Vairetti, M. (2010). Dexamethasone protects cultured rat hepatocytes against cadmium toxicity: Involvement of cellular thiols. In Vitro Cell. Dev. Biol. Anim., 46.","DOI":"10.1007\/s11626-009-9261-y"},{"key":"ref_40","unstructured":"Strober, W. (2001). Trypan Blue Exclusion Test of Cell Viability. Current Protocols in Immunology, John Wiley & Sons, Inc."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Bergmeyer, H.-U., Bernt, E., and Hess, B. (1965). Lactic Dehydrogenase, Springer.","DOI":"10.1016\/B978-0-12-395630-9.50134-1"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1007\/s11010-016-2758-2","article-title":"MCD diet-induced steatohepatitis is associated with alterations in asymmetric dimethylarginine (ADMA) and its transporters","volume":"419","author":"Berardo","year":"2016","journal-title":"Mol. Cell. Biochem."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/19\/2\/314\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:52:14Z","timestamp":1760194334000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/19\/2\/314"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,23]]},"references-count":42,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2018,2]]}},"alternative-id":["ijms19020314"],"URL":"https:\/\/doi.org\/10.3390\/ijms19020314","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,1,23]]}}}