Chronic ketamine exposure results in psychotic and cognitive symptoms that resemble those found in patients with schizophrenia. Emerging evidence suggests that patients with schizophrenia exhibit gut Show more
Chronic ketamine exposure results in psychotic and cognitive symptoms that resemble those found in patients with schizophrenia. Emerging evidence suggests that patients with schizophrenia exhibit gut microbiota dysbiosis and decreased levels of short-chain fatty acids (SCFAs) and BDNF, which are related to the severity of psychotic and cognitive symptoms. Dietary inulin can regulate gut microbiota, SCFAs, and BDNF. However, the role of gut microbiota, SCFAs, and BDNF in chronic ketamine-induced schizophrenia-like behaviors is unclear. In this study, we found that chronic ketamine exposure for 28 days caused gut microbiota dysregulation, reduced the expression of SCFAs in serum, hippocampus, and feces, elevated gut permeability, downregulated the BDNF-TrkB-ERK1/2-CREB signaling pathway, caused neuronal damage, and decreased the expression of synaptic proteins Syn and PSD-95, which may lead to anxiety-like behaviors, prepulse inhibition (PPI) deficits, and spatial learning and memory deficits. In addition, inulin intervention reversed gut microbiota dysbiosis by decreasing the abundance of Show less
Microglial decline in the dentate gyrus is an important mechanism in the development of depression-like behaviors in stressed animals. Reversing this decline with low-dose lipopolysaccharide (LPS) can Show more
Microglial decline in the dentate gyrus is an important mechanism in the development of depression-like behaviors in stressed animals. Reversing this decline with low-dose lipopolysaccharide (LPS) can produce rapid antidepressant effects, yet the underlying mechanisms remain incompletely understood. Our previous work identified a critical role for astrocytic P2Y1 receptor (P2Y1R) activation and subsequent dentate gyrus extracellular signal-regulated kinase 1/2 (ERK1/2)-brain-derived neurotrophic factor (BDNF) signaling in the antidepressant effect of low-dose LPS. This study elucidates the signaling cascade linking astrocytic P2Y1R mobilization to the antidepressant effect of low-dose LPS. We found that low-dose LPS promoted glutamate release through ATP-triggered astrocytic P2Y1R signaling. Blockade of N-methyl-D-aspartic acid (NMDA) receptors, but not metabotropic receptors, and the GluN2B subtype of NMDA receptors abolished the antidepressant effect of low-dose LPS. GluN2B knockdown also abolished the reversal effect of low-dose LPS on CUS-induced depression-like behaviors and impairment of dentate gyrus ERK1/2-BDNF signaling. Moreover, chelating intracellular Ca Show less