{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T00:12:07Z","timestamp":1790813527067,"version":"4.1.0"},"reference-count":33,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2022,12,11]],"date-time":"2022-12-11T00:00:00Z","timestamp":1670716800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002428","name":"Austrian Science Fund","doi-asserted-by":"publisher","award":["I2463-B21"],"award-info":[{"award-number":["I2463-B21"]}],"id":[{"id":"10.13039\/501100002428","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002428","name":"Austrian Science Fund","doi-asserted-by":"publisher","award":["SRP50"],"award-info":[{"award-number":["SRP50"]}],"id":[{"id":"10.13039\/501100002428","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Research Foundation Flanders","award":["I2463-B21"],"award-info":[{"award-number":["I2463-B21"]}]},{"name":"Research Foundation Flanders","award":["SRP50"],"award-info":[{"award-number":["SRP50"]}]},{"name":"Research Council of the Vrije Universiteit Brussel for financial support through the Strategic Research Program","award":["I2463-B21"],"award-info":[{"award-number":["I2463-B21"]}]},{"name":"Research Council of the Vrije Universiteit Brussel for financial support through the Strategic Research Program","award":["SRP50"],"award-info":[{"award-number":["SRP50"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>There is still an unmet clinical need to develop new pharmaceuticals for effective and safe pain management. Current pharmacotherapy offers unsatisfactory solutions due to serious side effects related to the chronic use of opioid drugs. Prescription opioids produce analgesia through activation of the mu-opioid receptor (MOR) and are major contributors to the current opioid crisis. Multifunctional ligands possessing activity at more than one receptor represent a prominent therapeutic approach for the treatment of pain with fewer adverse effects. We recently reported on the design of a bifunctional MOR agonist\/neuropeptide FF receptor (NPFFR) antagonist peptididomimetic, KGFF09 (H-Dmt-DArg-Aba-\u03b2Ala-Bpa-Phe-NH2), and its antinociceptive effects after subcutaneous (s.c.) administration in acute and persistent pain in mice with reduced propensity for unwanted side effects. In this study, we further investigated the antinociceptive properties of KGFF09 in a mouse model of visceral pain after s.c. administration and the potential for opioid-related liabilities of rewarding and sedation\/locomotor dysfunction following chronic treatment. KGFF09 produced a significant dose-dependent inhibition of the writhing behavior in the acetic acid-induced writhing assay with increased potency when compared to morphine. We also demonstrated the absence of harmful effects caused by typical MOR agonists, i.e., rewarding effects (conditioned-place preference test) and sedation\/locomotor impairment (open-field test), at a dose shown to be highly effective in inhibiting pain behavior. Consequently, KGFF09 displayed a favorable benefit\/side effect ratio regarding these opioid-related side effects compared to conventional opioid analgesics, such as morphine, underlining the development of dual MOR agonists\/NPFFR antagonists as improved treatments for various pain conditions.<\/jats:p>","DOI":"10.3390\/molecules27248785","type":"journal-article","created":{"date-parts":[[2022,12,12]],"date-time":"2022-12-12T04:34:20Z","timestamp":1670819660000},"page":"8785","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Bifunctional Peptidomimetic G Protein-Biased Mu-Opioid Receptor Agonist and Neuropeptide FF Receptor Antagonist KGFF09 Shows Efficacy in Visceral Pain without Rewarding Effects after Subcutaneous Administration in Mice"],"prefix":"10.3390","volume":"27","author":[{"given":"Maria","family":"Dumitrascuta","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charlotte","family":"Martin","sequence":"additional","affiliation":[{"name":"Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven","family":"Ballet","sequence":"additional","affiliation":[{"name":"Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2379-5358","authenticated-orcid":false,"given":"Mariana","family":"Spetea","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1038\/s41380-020-0661-4","article-title":"The changing opioid crisis: Development, challenges and opportunities","volume":"26","author":"Volkow","year":"2021","journal-title":"Mol. Psychiatry"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Sobczak, \u0141., and Gory\u0144ski, K. (2020). Pharmacological aspects of over-the-counter opioid drugs misuse. Molecules, 25.","DOI":"10.3390\/molecules25173905"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Paul, A.K., Smith, C.M., Rahmatullah, M., Nissapatorn, V., Wilairatana, P., Spetea, M., Gueven, N., and Dietis, N. (2021). Opioid analgesia and opioid-induced adverse effects: A review. Pharmaceuticals, 14.","DOI":"10.3390\/ph14111091"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1146\/annurev-neuro-080317-061522","article-title":"Endogenous and exogenous opioids in pain","volume":"41","author":"Corder","year":"2018","journal-title":"Annu. Rev. Neurosci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"101420","DOI":"10.1016\/j.berh.2019.06.002","article-title":"Pain therapy\u2014Are there new options on the horizon?","volume":"33","author":"Stein","year":"2019","journal-title":"Best Pract. Res. Clin. Rheumatol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.biopsych.2019.10.020","article-title":"Toward directing opioid receptor signaling to refine opioid therapeutics","volume":"87","author":"Grim","year":"2020","journal-title":"Biol. Psychiatry"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"739","DOI":"10.1146\/annurev-biochem-061620-044044","article-title":"Structural insights accelerate the discovery of opioid alternatives","volume":"90","author":"Che","year":"2021","journal-title":"Ann. Rev. Biochem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"837671","DOI":"10.3389\/fphar.2022.837671","article-title":"The kappa opioid receptor: A promising therapeutic target for multiple pathologies","volume":"13","author":"Dalefield","year":"2022","journal-title":"Front. Pharmacol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"106091","DOI":"10.1016\/j.phrs.2022.106091","article-title":"An updated assessment of the translational promise of G-protein-biased kappa opioid receptor agonists to treat pain and other indications without debilitating adverse effects","volume":"177","author":"French","year":"2022","journal-title":"Pharmacol. Res."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Varga, B.R., Streicher, J.M., and Majumdar, S. (2022). Strategies towards safer opioid analgesics\u2014A review of old and upcoming targets. Br. J Pharmacol., 1\u201319.","DOI":"10.1111\/bph.15760"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1190","DOI":"10.1002\/cmdc.201600161","article-title":"Multitarget drug discovery and polypharmacology","volume":"11","author":"Bolognesi","year":"2016","journal-title":"ChemMedChem"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"420","DOI":"10.1021\/acs.jmedchem.8b00760","article-title":"Polypharmacology by design: A medicinal chemist\u2019s perspective on multitargeting compounds","volume":"62","author":"Proschak","year":"2019","journal-title":"J. Med. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"7435","DOI":"10.2174\/138161281942140105165646","article-title":"Hybrid opioid\/non-opioid ligands in pain research","volume":"19","author":"Kleczkowska","year":"2013","journal-title":"Curr. Pharm. Des."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1016\/j.ejmech.2015.11.028","article-title":"Multitarget opioid ligands in pain relief: New players in an old game","volume":"108","author":"Turnaturi","year":"2016","journal-title":"Eur. J. Med. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Starnowska-Sok\u00f3\u0142, J., and Przew\u0142ocka, B. (2020). Multifunctional opioid-derived hybrids in neuropathic pain: Preclinical evidence, ideas and challenges. Molecules, 25.","DOI":"10.3390\/molecules25235520"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"170331","DOI":"10.1016\/j.peptides.2020.170331","article-title":"The search for opioid analgesics with limited tolerance liability","volume":"130","author":"Wtorek","year":"2020","journal-title":"Peptides"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Spetea, M., and Schmidhammer, H. (2021). Recent chemical and charmacological cevelopments on 14-oxygenated-N-methylmorphinan-6-ones. Molecules, 26.","DOI":"10.3390\/molecules26185677"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1097\/j.pain.0000000000000790","article-title":"Bifunctional peptide-based opioid agonist\/nociceptin antagonist ligand for dual treatment of nociceptive and neuropathic pain","volume":"158","author":"Lagard","year":"2017","journal-title":"Pain"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1705","DOI":"10.1097\/j.pain.0000000000001262","article-title":"A bifunctional-biased mu-opioid agonist-neuropeptide FF receptor antagonist as analgesic with improved acute and chronic side effects","volume":"159","author":"Guillemyn","year":"2018","journal-title":"Pain"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"12929","DOI":"10.1021\/acs.jmedchem.0c01376","article-title":"Optimized opioid-neurotensin multitarget peptides: From design to structure-activity relationship studies","volume":"63","author":"Gonzalez","year":"2020","journal-title":"J. Med. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Dumitrascuta, M., Bermudez, M., Trovato, O., Neve, J.D., Ballet, S., Wolber, G., and Spetea, M. (2021). Antinociceptive efficacy of the \u00b5-opioid\/nociceptin peptide-based hybrid KGNOP1 in inflammatory pain without rewarding effects in mice: An experimental assessment and molecular docking. Molecules, 26.","DOI":"10.3390\/molecules26113267"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1363","DOI":"10.1097\/ALN.0b013e318238bba6","article-title":"Molecular mechanisms of opioid receptor-dependent signaling and behavior","volume":"115","author":"Bruchas","year":"2011","journal-title":"Anesthesiology"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"125","DOI":"10.3389\/fphar.2019.00125","article-title":"GPCR signaling regulation: The role of GRKs and arrestins","volume":"10","author":"Gurevich","year":"2019","journal-title":"Front. Pharmacol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"641","DOI":"10.1021\/acs.jmedchem.8b01327","article-title":"Synthesis, biological, and structural explorations of new zwitterionic derivatives of 14-O-methyloxymorphone, as potent \u03bc\/\u03b4 opioid agonists and peripherally selective antinociceptives","volume":"62","author":"Spetea","year":"2019","journal-title":"J. Med. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1038\/383819a0","article-title":"Loss of morphine-induced analgesia, reward effect and withdrawal symptoms in mice lacking the mu-opioid-receptor gene","volume":"383","author":"Matthes","year":"1996","journal-title":"Nature"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1111\/j.1369-1600.2007.00070.x","article-title":"Review on CPP: Measuring reward with the conditioned place preference (CPP) paradigm: Update of the last decade","volume":"12","author":"Tzschentke","year":"2007","journal-title":"Addict. Biol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/0149-7634(94)00021-R","article-title":"Conditioned place preference using opiate and stimulant drugs: A meta-analysis","volume":"19","author":"Bardo","year":"1995","journal-title":"Neurosci. Biobehav. Rev."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1111\/j.1476-5381.1983.tb10011.x","article-title":"Determination of receptors that mediate opiate side effects in the mouse","volume":"7","author":"Hayes","year":"1983","journal-title":"Br. J. Pharmacol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"173","DOI":"10.2165\/00002018-199819030-00002","article-title":"Adverse effects of opioid agonists and agonist-antagonists in anaesthesia","volume":"19","author":"Bowdle","year":"1998","journal-title":"Drug Saf."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1016\/j.pbb.2004.12.002","article-title":"Preclinical comparison between different opioids: Antinociceptive versus adverse effects","volume":"80","author":"Meert","year":"2005","journal-title":"Pharmacol. Biochem. Behav."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1177\/0269881107073199","article-title":"The open field test: Reinventing the wheel","volume":"21","author":"Stanford","year":"2007","journal-title":"J. Psychopharmacol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/0003-2697(76)90527-3","article-title":"A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding","volume":"72","author":"Bradford","year":"1976","journal-title":"Anal. Biochem."},{"key":"ref_33","first-page":"99","article-title":"A simplified method of evaluating dose-effect experiments","volume":"96","author":"Litchfield","year":"1949","journal-title":"J. Pharmacol. Exp. Ther."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/24\/8785\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:38:08Z","timestamp":1760146688000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/24\/8785"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,11]]},"references-count":33,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2022,12]]}},"alternative-id":["molecules27248785"],"URL":"https:\/\/doi.org\/10.3390\/molecules27248785","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,11]]}}}