Adenosine signaling driven by the gut microbiota underlies chronic alcohol-induced anesthetic resistance.

Chronic alcohol consumption increases anesthetic tolerance, yet the underlying in vivo mechanisms remain unclear. Here, we demonstrate that long-term alcohol exposure reduces anesthetic efficacy in both humans and mice, prolonging induction and shortening maintenance. Fecal microbiota transplantation from alcohol-exposed donors recapitulated this phenotype in naive mice, indicating a causal role of gut microbiome alterations. Metagenomic and metabolomic analyses identified elevated adenosine as a key microbiota-derived metabolite. Adenosine supplementation decreased anesthetic sensitivity, likely via downregulation of gamma-aminobutyric acid (GABA) receptors. Our findings reveal a gut microbiota-adenosine pathway mediating alcohol-induced anesthetic resistance.