Fig. 5.

Influence of Lactobacillus inoculation or lactate treatment on the levels of the neurotransmitter, gamma-aminobutyric acid (GABA), in the hippocampus of the mice. a Representative images of immunostaining for GABA, taken from the cell body layers in the dentate gyrus of a germ-free mouse and mice treated with Lactobacillus reuteri, brevis, or plantarum. Nuclei are shown in blue, GABA is shown in green. Using images covering the CA fields and the dentage gyrus, the percent GABA-positive cells was calculated by the fraction of cell bodies showing GABA (green color) from the total number of cells (identified by the blue nuclei). b and cLactobacillus inoculation (n = 4, 2 males and 2 females for each treatment) (b) or lactate treatment (n = 6, 3 males and 3 females for each treatment) (c) significantly increased the levels of GABA in the hippocampus of mice. Error bars indicate mean ± SEM