Hypoxia Disrupted Serotonin Levels in the Prefrontal Cortex and Striatum, Leading to Depression-like Behavior

Hypoxia can adversely affect multiple organ systems. This study investigated the impact of intermittent hypoxia on serotonin levels and depression-like behaviors across distinct neuroanatomical regions. Sixteen adult female Wistar albino rats were divided into two groups: control (<i>n</i> = 8) and hypoxia (<i>n</i> = 8). The hypoxia group was exposed to a simulated altitude of 3000 for 5 h daily over 14 days. Behavioral assessments included locomotor activity (open field test) and depression-like behaviors (forced swimming test). Serotonin levels were quantified via ELISA in the prefrontal cortex, striatum, thalamus, hypothalamus, hippocampus, and serum. Intermittent hypoxia did not alter locomotor activity (<i>p</i> > 0.05) but significantly increased depression-like behavior (<i>p</i> < 0.05), accompanied by a pronounced reduction in swimming behavior (<i>p</i> < 0.0001), a marker associated with serotonergic function. Serotonin levels were significantly reduced in the prefrontal cortex (<i>p</i> < 0.005) and striatum (<i>p</i> < 0.05), while no changes were observed in other regions or serum (<i>p</i> > 0.05). These findings demonstrate that intermittent hypoxia induces depression-like behaviors and region-specific serotonin depletion, particularly in the prefrontal cortex and striatum. This underscores the need to evaluate hypoxia-related brain health implications in conditions such as sleep apnea and acute mountain sickness.