Lactobacillus reuteri E9 regulates sleep disorders by upregulating inhibitory neurotransmitters and sleep-related receptor expression via the microbiota-gut-brain axis.

Q: What is the main mechanism by which Lactobacillus reuteri E9 affects sleep?

It modulates the microbiota-gut-brain axis by upregulating inhibitory neurotransmitters like GABA and increasing expression of GABA and melatonin receptors.

Q: Was this study conducted in humans?

No, the study used a pentylenetetrazol (PTZ)-induced zebrafish model of sleep disorder.

Q: What neurotransmitters were affected by Lactobacillus reuteri E9?

GABA, taurine, glycine, and serine were significantly upregulated (p < 0.05).

Q: Is Lactobacillus reuteri E9 considered a psychobiotic?

Yes, the paper describes it as a psychobiotic with potential for sleep disorder management via the microbiota-gut-brain axis.

In a PTZ-induced zebrafish model of sleep disorder, Lactobacillus reuteri E9 significantly upregulated inhibitory neurotransmitters including GABA, taurine, glycine, and serine (p < 0.05). It also reduced seizures and hyperactivity, and upregulated GABA receptor genes and melatonin receptor (Mtnr1aa) genes in neural tissue, suggesting a psychobiotic mechanism for sleep regulation.

Last updated: Aug 25, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score24/100

Human RCT☆☆☆☆☆

Meta-analysis☆☆☆☆☆

Mechanism★★★★★

Safety★★★★☆

Confidencelow

Study Evidence

Study 1. Lactobacillus reuteri E9 Regulates Sleep Disorders Through Its Metabolite GABA.

observational

Jiang Y, Guo L, He H, Chen H, Chen T, Liu Y, Zhao W · Frontiers in bioscience (Landmark edition) (2025)

Participants: N/A

Duration: N/A

Intervention: Lactobacillus reuteri E9 (probiotic strain)

Outcome: Neurotransmitter levels (GABA, taurine, glycine, serine), seizure activity, hyperactivity, GABA receptor gene expression, melatonin receptor (Mtnr1aa) gene expression

Effect Size: N/A

Population: Pentylenetetrazol (PTZ)-induced zebrafish model of sleep disorder

Result:

PubMed: 40613302 DOI: 10.31083/FBL39587

Mechanism Graph

Lactobacillus reuteri E9 is administered to PTZ-induced zebrafish

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E9 upregulates inhibitory neurotransmitters (GABA, taurine, glycine, serine)

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E9 upregulates GABA receptor and melatonin receptor (Mtnr1aa) gene expression in neural tissue

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Result: Reduced seizures and hyperactivity, sedative effects, potential sleep regulation via MGBA

Limitations

⚠Animal model (zebrafish) may not fully translate to human sleep disorders
⚠Abstract does not report sample size or effect sizes, limiting quantitative assessment

Frequently Asked Questions

What is the main mechanism by which Lactobacillus reuteri E9 affects sleep?▼

It modulates the microbiota-gut-brain axis by upregulating inhibitory neurotransmitters like GABA and increasing expression of GABA and melatonin receptors.

Was this study conducted in humans?▼

No, the study used a pentylenetetrazol (PTZ)-induced zebrafish model of sleep disorder.

What neurotransmitters were affected by Lactobacillus reuteri E9?▼

GABA, taurine, glycine, and serine were significantly upregulated (p < 0.05).

Is Lactobacillus reuteri E9 considered a psychobiotic?▼

Yes, the paper describes it as a psychobiotic with potential for sleep disorder management via the microbiota-gut-brain axis.

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References

1.Jiang Y, Guo L, He H, Chen H, Chen T, Liu Y, Zhao W. "Lactobacillus reuteri E9 Regulates Sleep Disorders Through Its Metabolite GABA.." Frontiers in bioscience (Landmark edition), 2025. PMID: 40613302 DOI: 10.31083/FBL39587

Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.