Longitudinal Effects of Ketamine on Dendritic ArchitectureIn Vivoin the Mouse Medial Frontal Cortex
eNeuro March 1, 2016 Victoria Phoumthipphavong, Florent Barthas, Samantha Hassett et al. 142 citations
A single low dose of ketamine, an NMDA receptor antagonist, produces fast-acting antidepressant effects. In mice, a single injection of ketamine increased dendritic spine density in the medial frontal cortex for up to two weeks compared to saline-injected controls. This prolonged increase was driven by a higher rate of new spine formation, not by changes in spine elimination. Some new spines persisted, indicating functional synapses. In a few cases, distal apical tuft branches retracted the day after ketamine administration. These findings suggest that ketamine causes immediate removal of some dendritic inputs and gradual addition of others, consistent with a rebalancing of synaptic inputs onto frontal cortical neurons.