Acute ketamine administration attenuates lipopolysaccharide-induced depressive-like behavior by reversing abnormal regional homogeneity in the nucleus accumbens

Ketamine has rapid antidepressant effects, but no study to date has investigated changes in resting-state brain activity following ketamine administration in inflammation-induced depression. The purpose of this study was to use blood oxygen level-dependent functional MRI to explore changes in the resting-state brain activity in a rat model of depression induced by lipopolysaccharide (LPS, 1 mg/kg) challenge and to examine whether acute ketamine administration can reverse LPS-induced depressive-like behavior. Here, we showed LPS-induced depressive-like behavior as evidenced by significantly reduced motility in the forced swim test. In addition, LPS-induced increases in plasma levels of proinflammatory cytokines were not completely reversed by acute ketamine administration, suggesting that ketamine exerts its antidepressant effects independently of a possible interference with LPS-induced inflammatory signaling. However, increased regional homogeneity (ReHo) was observed in some brain regions of LPS-exposed animals, including bilateral caudate putamen and nucleus accumbens, which were parts of the mood-regulating circuit. Moreover, ReHo values of bilateral caudate putamen and nucleus accumbens showed significant positive correlations with immobility time. Notably, the LPS-induced depressive-like behavior and increase of ReHo value in the right nucleus accumbens was reversed by acute ketamine administration. In summary, this study suggests that acute ketamine administration is...

Source: NeuroReport - March 31, 2019 Category: Neurology Tags: CELLULAR, MOLECULAR AND DEVELOPMENTAL NEUROSCIENCE Source Type: research