OBJECTIVE: Ketamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, has shown rapid antidepressant effects, but small study groups and inadequate control conditions in prior studies have precluded a definitive conclusion. The authors evaluated the rapid antidepressant efficacy of ketamine in a large group of patients with treatment-resistant major depression. METHOD: This was a...
Recent studies show that higher order oscillatory interactions such as cross-frequency coupling are important for brain functions that are impaired in schizophrenia, including perception, attention and memory. Here we investigated the dynamics of oscillatory coupling in the hippocampus of awake rats upon NMDA receptor blockade by ketamine, a pharmacological model of schizophrenia. Ketamine (25,...
Major depressive disorder (MDD) is a serious mental disorder that ranks among the major causes of disease burden. Standard medical treatment targeting cerebral monoamines often provides only insufficient symptom relief and fails in approximately every fifth patient. The complexity of MDD therefore, reflects more than monoaminergic dysregulation. Initial research argues the case for excessive...
Biological PsychiatryJune 19, 2013Eric M Parise, Lyonna F. Alcantara, Brandon L. Warren et al.
Background Major Depressive Disorder (MDD) afflicts up to 10% of adolescents. However, nearly 50% of those afflicted are considered non-responsive to available treatments. Ketamine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist has shown potential as a rapid-acting and long-lasting treatment for MDD in adults. Thus, the effectiveness and functional consequences of ketamine...
Delusions are the persistent and often bizarre beliefs that characterise psychosis. Previous studies have suggested that their emergence may be explained by disturbances in prediction error-dependent learning. Here we set up complementary studies in order to examine whether such a disturbance also modulates memory reconsolidation and hence explains their remarkable persistence. First, we...
This article reviews the recreational use of ketamine ("Special K"; KET) and explores the recent diffusion of its new derivative methoxetamine ("Special M"; MXE). The literature search on the nonclinical/recreational use of KET and MXE was carried out in a range of medical databases. Considering the limitations of peer-reviewed information, data were integrated with a qualitative assessment of...
INTRODUCTION: Directional connectivity from anterior to posterior brain regions (or "feedback" connectivity) has been shown to be inhibited by propofol and sevoflurane. In this study the authors tested the hypothesis that ketamine would also inhibit cortical feedback connectivity in frontoparietal networks. METHODS: Surgical patients (n = 30) were recruited for induction of anesthesia with...
Several recent studies have shown that a single intravenous subanesthetic dose of ketamine, a NMDA receptor antagonist, exerts rapid antidepressant effects in patients with treatment refractory mood disorders and reduces suicidal ideation. Those insights have fueled tremendous excitement in the efforts to elucidate the mechanism underlying ketamine's antidepressant properties in animal models...
For more than 50 years, ketamine has proven to be a safe anesthetic drug with potent analgesic properties. The active enantiomer is S(+)-ketamine. Ketamine is mostly metabolized in norketamine, an active metabolite. During "dissociative anesthesia", sensory inputs may reach cortical receiving areas, but fail to be perceived in some association areas. Ketamine also enhances the descending...
Several studies have documented impairments in memory processes as a result of ketamine administration; however, few studies have compared the profile of cognitive effects of ketamine to other drugs. The aim of this study was to compare the cognitive effects of ketamine with those of triazolam in healthy volunteers. Doses of ketamine (0.2, 0.4 mg/kg intramuscular (i.m.)), triazolam (0.2, 0.4...