Neurotransmitter and Intestinal Interactions: Focus on the Microbiota-Gut-Brain Axis in Irritable Bowel Syndrome

Minjia Chen,Senhong Ying,Yi Ping,Zhifeng Xiao,Linling Lv,Fenghua Xu,Yuting Tian,Guangcong Ruan,Yanling Wei,Guanhu Li,Yi Cheng,Lu Chen

doi:10.3389/fendo.2022.817100

Abstract

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder of unknown etiology. IBS is caused by a disruption in the gut-brain axis. Given the importance of the gut microbiota in maintaining local and systemic homeostasis of immunity, endocrine, and other physiological processes, the microbiota-gut-brain axis has been proposed as a key regulator in IBS. Neurotransmitters have been shown to affect blood flow regulation, intestinal motility, nutrient absorption, the gastrointestinal immune system, and the microbiota in recent studies. It has the potential role to play a function in the pathophysiology of the gastrointestinal and neurological systems. Transmitters and their receptors, including 5-hydroxytryptamine, dopamine, γ-aminobutyric acid, and histamine, play an important role in IBS, especially in visceral sensitivity and gastrointestinal motility. Studies in this field have shed light on revealing the mechanism by which neurotransmitters act in the pathogenesis of IBS and discovering new therapeutic strategies based on traditional pharmacological approaches that target the nervous system or novel therapies that target the microbiota.

Highlights

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder (FGID) and one of the most prevalent gastrointestinal diseases
This review will focus on the possible role of neurotransmitters including 5-hydroxytryptamine (5-HT), dopamine, g-aminobutyric acid (GABA), and histamine in the microbiota-gut-brain axis (Table 1), and aims to summarize recent clinical and animal studies to explain how neurotransmitters are involved in FGIDs through synthetic mechanisms, gastrointestinal distribution, and therapeutic targets (Figure 2)
These findings suggested that regulation of the Kyn/tryptophan pathway may affect the receptors of NMDA in the central nervous system (CNS), might be involved in the progression of depression and may be a therapeutic target against the psychotic syndrome of the IBS patients [136, 137]

Summary

INTRODUCTION

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder (FGID) and one of the most prevalent gastrointestinal diseases. Several mechanisms have been proposed in IBS pathogenesis, including abnormal neural pathways and alterations in the immune and endocrine systems, Together, these elements lead to malfunctions in regulating intestinal smooth muscle movement (Figure 1). Recent studies highlight that the gut microbiota plays a role in inflammation and immune dysfunction via the gut-brain axis, which may contribute to IBS pathophysiology [6]. Available evidence has shown that neurotransmitters in the gastrointestinal system might be important in regulating the microbiota-gut-brain axis in IBS. This review will focus on the possible role of neurotransmitters including 5-hydroxytryptamine (5-HT), dopamine, g-aminobutyric acid (GABA), and histamine in the microbiota-gut-brain axis (Table 1), and aims to summarize recent clinical and animal studies to explain how neurotransmitters are involved in FGIDs through synthetic mechanisms, gastrointestinal distribution, and therapeutic targets (Figure 2)

IRRITABLE BOWEL SYNDROME

GABA Histamine

Other Neurotransmitters

CONCLUSION AND FUTURE PERSPECTIVE

Findings

AUTHOR CONTRIBUTIONS