Ketamine counteracts sevoflurane-induced depressive-like behavior and synaptic plasticity impairments through the adenosine A2A receptor/ERK pathway in rats.

Ketamine is an ionic glutamic acid N-methyl-d-aspartate receptor (NMDAR) antagonist commonly used in clinical anesthesia, and its rapid and lasting antidepressant effect has stimulated great interest in psychology research. However, the molecular mechanisms underlying its antidepressant action are still undetermined. Sevoflurane exposure early in life might induce developmental neurotoxicity and mood disorders. In this study, we evaluated the effect of ketamine against sevoflurane-induced depressive-like behavior and the underlying molecular mechanisms. Here, we reported that A2AR protein expression was upregulated in rats with depression induced by sevoflurane inhalation, which was reversed by ketamine. Pharmacological experiments showed that A2AR agonists could reverse the antidepressant effect of ketamine, decrease extracellular signal-regulated kinase (ERK) phosphorylation, reduce synaptic plasticity, and induce depressive-like behavior. Our results suggest that ketamine mediates ERK1/2 phosphorylation by downregulating A2AR expression and that p-ERK1/2 increases the production of synaptic-associated proteins, enhancing synaptic plasticity in the hippocampus and thereby ameliorating the depressive-like behavior induced by sevoflurane inhalation in rats. This research provides a framework for reducing anesthesia-induced developmental neurotoxicity and developing new antidepressants.