Neurotransmitter-mediated gut-brain axis: a bibliometric analysis of research trends and knowledge structure

Introduction: The gut-brain axis constitutes a bidirectional network linking the gastrointestinal tract and central nervous system through neural, endocrine, metabolic, and immune pathways. Neurotransmitters play a central role in mediating this crosstalk, serving as intermediates through which the gut microbiota influences brain function. Although important mechanistic advances have been made, research on the neurotransmitter-mediated gut-brain axis remains fragmented across disciplines. This study aimed to provide a comprehensive bibliometric overview of this field. Methods: We conducted a bibliometric analysis of 788 publications retrieved from Web of Science, Scopus, and PubMed between 2005 and 2025. Using VOSviewer, CiteSpace, and Pajek, we analyzed publication trends, geographic distribution, institutional and author contributions, journal co-citations, and keyword evolution to characterize the knowledge structure and emerging themes of the field. Results: The results revealed three developmental phases: an exploratory phase (2005-2016) with limited output, a developmental phase (2017-2019) with moderate growth, and a rapid expansion phase (2020-2025) marked by exponential increases in publications driven by advances in microbiome and neurotransmitter research. China led in publication volume, while the United States and Ireland served as major hubs of collaboration. University College Cork showed the highest citation impact, with 10,935 citations from 28 publications (average citations per document = 390.54). John F. Cryan, Timothy G. Dinan, and Gerard Clarke were among the leading contributors, with Cryan ranking first in both publication output and citation count. Keyword and thematic analyses identified gut microbiota, serotonin, short-chain fatty acids, depression, and inflammatory bowel disease as core topics, reflecting a shift from mechanistic studies to disease-specific and neurotransmitter-targeted research. Highly cited studies focused on microbial regulation of neurotransmitters, neuroimmune signaling, and their implications for neurodevelopmental and neurodegenerative disorders. Discussion: This study provides the first comprehensive bibliometric overview of neurotransmitter-mediated gut-brain axis research, offering a macroscopic perspective on its evolution, core knowledge base, and emerging frontiers. Future research should integrate multidisciplinary approaches, apply omics technologies, and develop precision interventions targeting neurotransmitter pathways while considering individual microbial profiles, in order to translate mechanistic insights into therapeutic strategies for neuropsychiatric disorders.