Ketamine alleviates PTSD-like effect and improves hippocampal synaptic plasticity via regulation of GSK-3β/GR signaling of rats.

Post-traumatic stress disorder affects 3-4% of people globally each year. In a rat model of PTSD induced by single prolonged stress, a single low dose of ketamine (10 mg/kg) prevented anxiety-like behaviors. Ketamine also reversed stress-induced changes in the hippocampus: it increased expression of glucocorticoid receptor, brain-derived neurotrophic factor, phosphorylated GSK-3β, FKBP5, and CRH, while decreasing GSK-3β protein expression, and it improved synaptic structure. A GSK-3β inhibitor produced similar behavioral effects, suggesting ketamine works by regulating GSK-3β/GR signaling to improve synaptic plasticity.

Study at a glance

Abstract

Each year, 3-4% of the global population experiences post-traumatic stress disorder (PTSD), a chronic mental disorder with significant social and economic repercussions. Although it has been shown that ketamine can effectively alleviate PTSD symptoms in individuals, the specific mechanism of action underlying its anti-PTSD effects remains unclear. In this study, we investigated how a single, low dose of ketamine affected the glycogen synthase kinase 3β (GSK-3β)/glucocorticoid receptor (GR) signaling pathway in a single prolonged stress (SPS)-induced PTSD rat model. After establishing the model, stress-related behavioral alterations in the rats were assessed following intraperitoneal injections of ketamine (10 mg/kg) and GSK-3β antagonist SB216763 (5 mg/kg). In the hippocampus, alterations in the expression of specific proteins implicated in PTSD development, such as GR, brain-derived neurotrophic factor (BDNF), GSK-3β, and phosphorylated glycogen synthase kinase 3β (p-GSK-3β), were assessed. We also measured changes in the mRNA expression levels of GR, BDNF, GSK-3β, FK501 binding protein 51 (FKBP5), and corticotropin-releasing hormone (CRH), as well as synaptic ultrastructure, in the hippocampus, and measured changes in corticosterone levels in the blood. SPS induced anxiety-like and depression-like behaviors in rats and induced morphological changes in synapse, which were accompanied by higher GSK-3β protein expression and conversely, decreased expression of GR, BDNF, p-GSK-3β, FKBP5 and CRH. Intraperitoneal administration of ketamine (10 mg/kg) after SPS prevented SPS-induced anxiety-like behaviors. Most importantly, ketamine attenuated SPS-induced dysfunctions in GSK-3β/GR signaling and synaptic deficits. Furthermore, treatment with a GSK-3β inhibitor played the same effect as ketamine on behavioral changes of SPS model rats. Single doses of ketamine effectively ameliorate SPS-induced anxiety-like symptoms, potentially by improving synaptic plastic in the hippocampus by regulating GSK-3β/GR signaling.