Figure 4.

This figure depicts the impact of a Val66Met polymorphism in the BDNF gene on the effects of ketamine upon dendritic spine growth in rodents (figure A) and on improvement in depression (Hamilton Depression Scale Score: HamD Score).

A. The left slide of this figure presents the results of two-photon microscopy of labeled layer 5 pyramidal neurons in slices from the prefrontal cortex. A robust proliferation of large and long dendritic spines is observed following ketamine administration in Wild Type (WT) animals. However, mice that have had the Met allele inserted into the BDNF gene (Met/Met), rendering that gene less effective, show 1) reduced dendritic spine density compared with the WT animals at baseline, and 2) markedly blunted increases in dendritic spine density following administration. *:p<0.05, **/##:p<0.01, n.s.=not significant. This figure is reprinted from Liu, et al. (113).

B. This figure presents the association of the rs6265 SNP in the BDNF gene with clinical response to ketamine in patients with major depression (data from (114)). In this group, 41 patients possessed the Val/Val genotype, 19 patients were Val/Met, and 2 patients were Met/Met. Fifty-eight patients were of European ancestry and 4 patients were African-American. The interaction of genotype and ketamine effects was highly significant (F = 5.59, df = 4, p = .0007).