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Saito A, Alvi S, Valant C, Christopoulos A, Carbone SE, Poole DP. Therapeutic potential of allosteric modulators for the treatment of gastrointestinal motility disorders. Br J Pharmacol 2024; 181:2232-2246. [PMID: 36565295 DOI: 10.1111/bph.16023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/24/2022] [Accepted: 12/09/2022] [Indexed: 12/25/2022] Open
Abstract
Gastrointestinal motility is tightly regulated by the enteric nervous system (ENS). Disruption of coordinated enteric nervous system activity can result in dysmotility. Pharmacological treatment options for dysmotility include targeting of G protein-coupled receptors (GPCRs) expressed by neurons of the enteric nervous system. Current GPCR-targeting drugs for motility disorders bind to the highly conserved endogenous ligand-binding site and promote indiscriminate activation or inhibition of the target receptor throughout the body. This can be associated with significant side-effect liability and a loss of physiological tone. Allosteric modulators of GPCRs bind to a distinct site from the endogenous ligand, which is typically less conserved across multiple receptor subtypes and can modulate endogenous ligand signalling. Allosteric modulation of GPCRs that are important for enteric nervous system function may provide effective relief from motility disorders while limiting side-effects. This review will focus on how allosteric modulators of GPCRs may influence gastrointestinal motility, using 5-hydroxytryptamine (5-HT), acetylcholine (ACh) and opioid receptors as examples. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Ayame Saito
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Sadia Alvi
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Simona E Carbone
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
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Sgambato V. The Serotonin 4 Receptor Subtype: A Target of Particular Interest, Especially for Brain Disorders. Int J Mol Sci 2024; 25:5245. [PMID: 38791281 PMCID: PMC11121119 DOI: 10.3390/ijms25105245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/22/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
In recent years, particular attention has been paid to the serotonin 4 receptor, which is well expressed in the brain, but also peripherally in various organs. The cerebral distribution of this receptor is well conserved across species, with high densities in the basal ganglia, where they are expressed by GABAergic neurons. The 5-HT4 receptor is also present in the cerebral cortex, hippocampus, and amygdala, where they are carried by glutamatergic or cholinergic neurons. Outside the central nervous system, the 5-HT4 receptor is notably expressed in the gastrointestinal tract. The wide distribution of the 5-HT4 receptor undoubtedly contributes to its involvement in a plethora of functions. In addition, the modulation of this receptor influences the release of serotonin, but also the release of other neurotransmitters such as acetylcholine and dopamine. This is a considerable asset, as the modulation of the 5-HT4 receptor can therefore play a direct or indirect beneficial role in various disorders. One of the main advantages of this receptor is that it mediates a much faster antidepressant and anxiolytic action than classical selective serotonin reuptake inhibitors. Another major benefit of the 5-HT4 receptor is that its activation enhances cognitive performance, probably via the release of acetylcholine. The expression of the 5-HT4 receptor is also altered in various eating disorders, and its activation by the 5-HT4 agonist negatively regulates food intake. Additionally, although the cerebral expression of this receptor is modified in certain movement-related disorders, it is still yet to be determined whether this receptor plays a key role in their pathophysiology. Finally, there is no longer any need to demonstrate the value of 5-HT4 receptor agonists in the pharmacological management of gastrointestinal disorders.
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Affiliation(s)
- Véronique Sgambato
- Institut des Sciences Cognitives Marc Jeannerod (ISCMJ), Unité Mixte de Recherche 5229 du Centre National de la Recherche Scientifique (CNRS), 69675 Bron, France; ; Tel.: +33-4379-11249
- UFR Biosciences, Université de Lyon 1, 69100 Villeurbanne, France
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Wang X, Guo R, Yu Z, Zikela L, Li J, Li S, Han Q. Torreya grandis Kernel Oil Alleviates Loperamide-Induced Slow Transit Constipation via Up-Regulating the Colonic Expressions of Occludin/Claudin-1/ZO-1 and 5-HT3R/5-HT4R in BALB/c Mice. Mol Nutr Food Res 2024; 68:e2300615. [PMID: 38152983 DOI: 10.1002/mnfr.202300615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/11/2023] [Indexed: 12/29/2023]
Abstract
SCOPE Torreya grandis kernel has traditionally been used to remove intestinal parasites and increases intestinal motility. However, the effect of Torreya grandis kernel oil (TKO) on constipation has not yet been investigated. Therefore, mouse model is used to investigate the effect of TKO on slow transit constipation (STC) and its possible mechanism. METHODS AND RESULTS The effects of TKO on intestinal motility of STC mice are evaluated by fecal weight, fecal water content, colon length, defecation test, and intestinal propulsion test. The mechanism of TKO alleviating STC is explored by detecting biochemical analysis, histological analysis, western blot, qRT-PCR, immunohistochemistry, and gut microbiota analysis. The results reveal that TKO effectively promotes defecation and intestinal motility, increases the level of endothelin-1, and restores the histopathological morphology of the colon under LOP pretreatment. The expression levels of occludin, claudin-1, and zonula occludens-1 (ZO-1) mRNA and protein are up-regulated in mice receiving TKO treatment. The colonic 5-hydroxytryptamine 3R/4R (5-HT3R/5-HT4R) expressions are also increased by TKO supplementation. Additionally, TKO rescues LOP-caused disorders of the gut microbiota. CONCLUSION Consumption of TKO is beneficial to STC recovery, and it can alleviate LOP-induced STC by up-regulating the colonic expressions of Occludin/Claudin-1/ZO-1 and 5-HT3R/5-HT4R.
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Affiliation(s)
- Xuezhu Wang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Rui Guo
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
- Academy of Chinese Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Zhuoli Yu
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Lalai Zikela
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Jiaomei Li
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
- Academy of Chinese Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Songtao Li
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
- Academy of Chinese Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
| | - Qiang Han
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
- Academy of Chinese Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310053, China
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Hurd M, Haag MM, Kwasnik MJ, Wykosky J, Lavoie B, Mawe GM. Protective actions of a luminally acting 5-HT 4 receptor agonist in mouse models of colitis. Neurogastroenterol Motil 2023; 35:e14673. [PMID: 37831752 PMCID: PMC10840927 DOI: 10.1111/nmo.14673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 10/15/2023]
Abstract
BACKGROUND 5-hydroxytryptamine 4 receptors (5-HT4 Rs) are expressed in the colonic epithelium, and previous studies have demonstrated that luminal administration of agonists enhances motility, suppresses nociception, and is protective in models of inflammation. We investigated whether stimulation with a luminally acting 5-HT4 R agonist is comparable to previously tested absorbable compounds. METHODS The dextran sodium sulfate (DSS), trinitrobenzene sulfonic acid (TNBS), and interleukin 10 knockout (IL-10KO) models of colitis were used to test the protective effects of the luminally acting 5-HT4 R agonist, 5HT4-LA1, in the absence and presence of a 5-HT4 R antagonist. The compounds were delivered by enema to mice either before (prevention) or after (recovery) the onset of active colitis. Outcome measure included disease activity index (DAI) and histological evaluation of colon tissue, and effects on wound healing and fecal water content were also assessed. KEY RESULTS Daily enema of 5HT4-LA1 attenuated the development of, and accelerated recovery from, active colitis. Enema administration of 5HT4-LA1 did not attenuate the development of colitis in 5-HT4 R knockout mice. Stimulation of 5-HT4 Rs with 5HT4-LA1 increased Caco-2 cell migration (accelerated wound healing). Daily administration of 5HT4-LA1 did not increase fecal water content in active colitis. CONCLUSIONS AND INFERENCES Luminally restricted 5-HT4 R agonists are comparable to absorbable compounds in attenuating and accelerating recovery from active colitis. Luminally acting 5-HT4 R agonists may be useful as an adjuvant to current inflammatory bowel disease (IBD) treatments to enhance epithelial healing.
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Affiliation(s)
- Molly Hurd
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont, USA
| | - Melody M Haag
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont, USA
| | - Matthew J Kwasnik
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont, USA
| | - Jill Wykosky
- Takeda Pharmaceuticals Company Limited, Cambridge, Massachusetts, USA
| | - Brigitte Lavoie
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont, USA
| | - Gary M Mawe
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont, USA
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Legan TB, Lavoie B, Norberg E, Ley IC, Tack S, Tompkins TA, Wargo MJ, Mawe GM. Tryptophan-synthesizing bacteria enhance colonic motility. Neurogastroenterol Motil 2023; 35:e14629. [PMID: 37357378 PMCID: PMC10527075 DOI: 10.1111/nmo.14629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/24/2023] [Accepted: 06/02/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND An emerging strategy to treat symptoms of gastrointestinal (GI) dysmotility utilizes the administration of isolated bacteria. However, the underlying mechanisms of action of these bacterial agents are not well established. Here, we elucidate a novel approach to promote intestinal motility by exploiting the biochemical capability of specific bacteria to produce the serotonin (5-HT) precursor, tryptophan (Trp). METHODS Mice were treated daily for 1 week by oral gavage of Bacillus (B.) subtilis (R0179), heat-inactivated R0179, or a tryptophan synthase-null strain of B. subtilis (1A2). Tissue levels of Trp, 5-HT, and 5-hydroxyindoleacetic acid (5-HIAA) were measured and changes in motility were evaluated. KEY RESULTS Mice treated with B. subtilis R0179 exhibited greater colonic tissue levels of Trp and the 5-HT breakdown product, 5-HIAA, compared to vehicle-treated mice. Furthermore, B. subtilis treatment accelerated colonic motility in both healthy mice as well as in a mouse model of constipation. These effects were not observed with heat-inactivated R0179 or the live 1A2 strain that does not express tryptophan synthase. Lastly, we found that the prokinetic effects of B. subtilis R0179 were blocked by coadministration of a 5-HT4 receptor (5-HT4 R) antagonist and were absent in 5-HT4 R knockout mice. CONCLUSIONS AND INFERENCES Taken together, these data demonstrate that intestinal motility can be augmented by treatment with bacteria that synthesize Trp, possibly through increased 5-HT signaling and/or actions of Trp metabolites, and involvement of the 5-HT4 R. Our findings provide mechanistic insight into a transient and predictable bacterial strategy to promote GI motility.
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Affiliation(s)
- Theresa B. Legan
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Brigitte Lavoie
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Emilia Norberg
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Isabella C. Ley
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | - Stephanie Tack
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
| | | | - Matthew J. Wargo
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
| | - Gary M. Mawe
- Department of Neurological Sciences, University of Vermont, Burlington, VT, USA
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Legan TB, Lavoie B, Mawe GM. Direct and indirect mechanisms by which the gut microbiota influence host serotonin systems. Neurogastroenterol Motil 2022; 34:e14346. [PMID: 35246905 PMCID: PMC9441471 DOI: 10.1111/nmo.14346] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 02/22/2022] [Indexed: 12/18/2022]
Abstract
Mounting evidence highlights the pivotal role of enteric microbes as a dynamic interface with the host. Indeed, the gut microbiota, located in the lumen of the gastrointestinal (GI) tract, influence many essential physiological processes that are evident in both healthy and pathological states. A key signaling molecule throughout the body is serotonin (5-hydroxytryptamine; 5-HT), which acts in the GI tract to regulate numerous gut functions including intestinal motility and secretion. The gut microbiota can modulate host 5-HT systems both directly and indirectly. Direct actions of gut microbes, evidenced by studies using germ-free animals or antibiotic administration, alter the expression of key 5-HT-related genes to promote 5-HT biosynthesis. Indirectly, the gut microbiota produce numerous microbial metabolites, whose actions can influence host serotonergic systems in a variety of ways. This review summarizes the current knowledge regarding mechanisms by which gut bacteria act to regulate host 5-HT and 5-HT-mediated gut functions, as well as implications for 5-HT in the microbiota-gut-brain axis.
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Affiliation(s)
- Theresa B Legan
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont, USA
| | - Brigitte Lavoie
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont, USA
| | - Gary M Mawe
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont, USA
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Wei L, Singh R, Ghoshal UC. Enterochromaffin Cells-Gut Microbiota Crosstalk: Underpinning the Symptoms, Pathogenesis, and Pharmacotherapy in Disorders of Gut-Brain Interaction. J Neurogastroenterol Motil 2022; 28:357-375. [PMID: 35719046 PMCID: PMC9274469 DOI: 10.5056/jnm22008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/16/2022] [Accepted: 04/04/2022] [Indexed: 11/20/2022] Open
Abstract
Disorders of gut-brain interaction (DGBIs) are common conditions in community and clinical practice. As specialized enteroendocrine cells, enterochromaffin (EC) cells produce up to 95% of total body serotonin and coordinate luminal and basolateral communication in the gastrointestinal (GI) tract. EC cells affect a broad range of gut physiological processes, such as motility, absorption, secretion, chemo/mechanosensation, and pathologies, including visceral hypersensitivity, immune dysfunction, and impaired gastrointestinal barrier function. We aim to review EC cell and serotonin-mediated physiology and pathophysiology with particular emphasis on DGBIs. We explored the knowledge gap and attempted to suggest new perspectives of physiological and pathophysiological insights of DGBIs, such as (1) functional heterogeneity of regionally distributed EC cells throughout the entire GI tract; (2) potential pathophysiological mechanisms mediated by EC cell defect in DGBIs; (3) cellular and molecular mechanisms characterizing EC cells and gut microbiota bidirectional communication; (4) differential modulation of EC cells through GI segment-specific gut microbiota; (5) uncover whether crosstalk between EC cells and (i) luminal contents; (ii) enteric nervous system; and (iii) central nervous system are core mechanisms modulating gut-brain homeostasis; and (6) explore the therapeutic modalities for physiological and pathophysiological mechanisms mediated through EC cells. Insights discussed in this review will fuel the conception and realization of pathophysiological mechanisms and therapeutic clues to improve the management and clinical care of DGBIs.
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Affiliation(s)
- Lai Wei
- Enteric NeuroScience Program, Mayo Clinic, Rochester, MN, USA
| | - Rajan Singh
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, NV, USA
| | - Uday C Ghoshal
- Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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Mawe GM, Hurd M, Hennig GW, Lavoie B. Epithelial 5-HT 4 Receptors as a Target for Treating Constipation and Intestinal Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1383:329-334. [PMID: 36587170 DOI: 10.1007/978-3-031-05843-1_30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Because of their importance in the regulation of gut functions, several therapeutic targets involving serotonin-related proteins have been developed or repurposed to treat motility disorders, including serotonin transporter inhibitors, tryptophan hydroxylase blockers, 5-HT3 antagonists, and 5-HT4 agonists. This chapter focuses on our discovery of 5-HT4 receptors in the epithelial cells of the colon and our efforts to evaluate the effects of stimulating these receptors. 5-HT4 receptors appear to be expressed by all epithelial cells in the mouse colon, based on expression of a reporter gene driven by the 5-HT4 receptor promoter. Application of 5-HT4 agonists to the mucosal surface causes serotonin release from enterochromaffin cells, mucus secretion from goblet cells, and chloride secretion from enterocytes. Luminal administration of 5-HT4 agonists speeds up colonic motility and suppresses distention-induced nociceptive responses. Luminal administration of 5-HT4 agonists also decreases the development of, and improves recovery from, experimental colitis. Recent studies determined that the prokinetic actions of minimally absorbable 5-HT4 agonists are just as effective as absorbable compounds. Collectively, these findings indicate that targeting epithelial receptors with non-absorbable 5-HT4 agonists could offer a safe and effective strategy for treating constipation and colitis.
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Affiliation(s)
- Gary M Mawe
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA.
- Department of Pharmacology, The University of Vermont, Burlington, VT, USA.
| | - Molly Hurd
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
| | - Grant W Hennig
- Department of Pharmacology, The University of Vermont, Burlington, VT, USA
| | - Brigitte Lavoie
- Department of Neurological Sciences, The University of Vermont, Burlington, VT, USA
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Understanding the Molecular Basis of 5-HT 4 Receptor Partial Agonists through 3D-QSAR Studies. Int J Mol Sci 2021; 22:ijms22073602. [PMID: 33808456 PMCID: PMC8036435 DOI: 10.3390/ijms22073602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder whose prevalence has an incidence in senior citizens. Unfortunately, current pharmacotherapy only offers symptom relief for patients with side effects such as bradycardia, nausea, and vomiting. Therefore, there is a present need to provide other therapeutic alternatives for treatments for these disorders. The 5-HT4 receptor is an attractive therapeutic target since it has a potential role in central and peripheral nervous system disorders such as AD, irritable bowel syndrome, and gastroparesis. Quantitative structure-activity relationship analysis of a series of 62 active compounds in the 5-HT4 receptor was carried out in the present work. The structure-activity relationship was estimated using three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques based on these structures' field molecular (force and Gaussian field). The best force-field QSAR models achieve a value for the coefficient of determination of the training set of R2training = 0.821, and for the test set R2test = 0.667, while for Gaussian-field QSAR the training and the test were R2training = 0.898 and R2test = 0.695, respectively. The obtained results were validated using a coefficient of correlation of the leave-one-out cross-validation of Q2LOO = 0.804 and Q2LOO = 0.886 for force- and Gaussian-field QSAR, respectively. Based on these results, novel 5-HT4 partial agonists with potential biological activity (pEC50 8.209-9.417 for force-field QSAR and 9.111-9.856 for Gaussian-field QSAR) were designed. In addition, for the new analogues, their absorption, distribution, metabolism, excretion, and toxicity properties were also analyzed. The results show that these new derivatives also have reasonable pharmacokinetics and drug-like properties. Our findings suggest novel routes for the design and development of new 5-HT4 partial agonists.
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