Fluoxetine modulates both endocannabinoid and lysophosphatidic acid pathways in a region-specific Manner during alcohol withdrawal in male rats.

Anxiety is a major symptom associated with alcohol withdrawal and a major factor increasing the risk of relapse. Although fluoxetine, a selective serotonin reuptake inhibitor, is used to alleviate these symptoms, its effects on brain lipid signaling pathways involved in withdrawal-related anxiety remain unclear. This study evaluated, in a preclinical model, the behavioral and molecular effects of chronic alcohol exposure and fluoxetine treatment during early abstinence. Male Wistar rats received oral alcohol (3 g/kg) or saline for 14 days, followed by 7 days without alcohol, during which fluoxetine (10 mg/kg) was administered to designated groups. Anxiety-like behavior was assessed using the elevated plus maze. Circulating plasma levels of corticosterone, 2-arachidonoylglycerol (2-AG), lysophosphatidic acid (LPA), and interleukin-10 (IL-10) were quantified, and gene expression analyses were performed in the amygdala and medial prefrontal cortex (mPFC). Chronic alcohol administration increased anxiety-like behavior and plasma 2-AG, while reducing LPA and IL-10 levels. Fluoxetine induced an anxiolytic effect in controls but was ineffective in alcohol-exposed rats, only normalizing the alcohol-induced increase of plasma 2-AG. At the molecular level, fluoxetine modulated gene expression region-specifically, altering 2-AG-related genes in the amygdala and enhancing LPA signaling in the mPFC. Hierarchical clustering revealed coordinated downregulation of 2-AG pathway genes in the alcohol-fluoxetine group and partial restoration of anti-inflammatory markers. These findings indicate fluoxetine modulates lipid signaling and immune-related genes during alcohol withdrawal, but its anxiolytic efficacy may be limited after alcohol exposure. These findings may contribute to the development of targeted therapeutic strategies for alcohol-related anxiety and relapse prevention.