Single Ayahuasca administration attenuates alcohol relapse and associated behavioral, neurochemical, and oxidative alterations in rats

BACKGROUND: Alcohol use disorder (AUD) remains difficult to treat with lasting success, leading to growing interest in alternative therapeutic approaches. Psychedelic compounds such as Ayahuasca, a traditional brew used in Indigenous Amazonian ceremonies containing N,N-dimethyltryptamine (DMT) along with monoamine oxidase-inhibiting β-carbolines, have shown promise in reducing addictive behaviors. METHODS: Alcohol dependence was induced in Wistar rats through a voluntary ethanol-consumption paradigm (15% and 30% v/v) of 35 days, followed by a deprivation period of 9 days. Subsequently, rats received a single administration of Ayahuasca containing 2.72 mg/kg N,N-dimethyltryptamine, 3.98 mg/kg harmine, 0.20 mg/kg harmaline, and 3.72 mg/kg tetrahydroharmine or water by gavage, and a relapse protocol of 9 days evaluated relapse-like ethanol intake. Subsequently, rats underwent behavioral testing to assess anxiety- and depressive-like behavior using the elevated plus maze, open field test, splash test, and forced swim test. The levels of dopamine (DA), serotonin (5-HT), brain-derived neurotrophic factor (BDNF), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR)) activities, and oxidative stress biomarkers (2',7'-dichlorodihydrofluorescein (DCFH) oxidation and thiobarbituric acid reactive substances (TBARS) levels) were assessed in the frontal cortex, hippocampus and striatum 15 days after Ayahuasca administration. RESULTS: A single Ayahuasca administration reduced relapse-like ethanol intake in a sex- and concentration-dependent manner; attenuated alcohol-induced anxiety- and depressive-like behavioral alterations, despite limited evidence of locomotor/exploratory changes; increased striatal DA levels in alcohol-exposed males and females and restored cortical 5-HT levels primarily in males; and partially mitigated alcohol-associated reductions in BDNF levels in a region- and sex-dependent manner. Antioxidant enzyme activities did not show consistent treatment-related modulation, whereas oxidative stress markers (DCFH and TBARS) were reduced in the frontal cortex, hippocampus, and striatum following Ayahuasca administration. However, some oxidative stress and BDNF outcomes showed partial rather than complete normalization. Sex-dependent effects were observed for selected ethanol-intake, neurochemical, BDNF, and oxidative-stress outcomes. CONCLUSION: Ayahuasca reduced alcohol intake during relapse and attenuated several alcohol-induced behavioral, neurochemical, neurotrophic, and oxidative disturbances in a preclinical model of alcohol dependence, withdrawal, and relapse. These findings suggest modulation of neurobiological pathways disrupted by chronic alcohol exposure, while highlighting region- and sex-dependent effects and incomplete normalization for selected outcomes. Dose-response, longitudinal, and mechanistic studies are warranted, alongside controlled clinical studies evaluating safety and efficacy in AUD.