Fig. 7

The modulated dopamine by gut microbiota-mediated vitamin B₆ regulated social behavior of EphB6-deficient mice. a–c The 8-week-old male WT and KO mice were orally gavaged with the fecal microbiota of 8-week-old male WT mice or sterile PBS for 1 week (a). After 1 week, the level of amino acid neurotransmitters (b, n = 7, 7, 5 mice respectively) and monoamine neurotransmitters (c, n = 5, 5, 7 mice respectively) in PFC of mice were detected. d One hour after the injection of 1 mg PLP intraperitoneally, the level of DA in PFC of 8-week-old male KO mice was increased compared with that of KO mice injected with saline. n = 5 mice for each group. e The level of DA in PFC of SPF male C57BL/6J mice fed without vitamin B₆ was decreased compared with that of C57BL/6J mice fed with normal diet. n = 3, 4 mice respectively. f The mRNA expression of dopamine receptors and Th in mPFC or VTA of 8-week-old WT and KO mice were detected by qRT-PCR. n = 4, 3 mice respectively. g–j Thirty minutes after the injection of D1R agonist (SKF38393, 0.0625 μg/0.3 μL) in mPFC of 8-week-old male KO mice, olfactory habituation/dishabituation test (g) or three-chambered social approach task (h–j) was conducted with an interval of 1 week. n = 9, 11 mice respectively. k–m The 8-week-old SPF male C57BL/6J mice that injected with D1R agonist (SKF38393, 0.0625 μg/0.3 μL) in mPFC were performed with olfactory habituation/dishabituation test (k) or three-chambered social approach task (l, m) with an interval of 1 week. n = 7, 8 mice respectively. n–q The 8-week-old SPF male C57BL/6J mice were injected with D1R antagonist (SCH23390) in mPFC, and olfactory habituation/dishabituation test (n, n = 8, 8, 9, 8 mice respectively) or three-chambered social approach task (o–q, n = 9, 5, 9, 5 mice respectively) were conducted with an interval of 1 week. Data shown are mean ± SEM. Two-tailed unpaired student’s t test (d–f, i, j, m), one-way ANOVA (b, c, p, q), mixed design ANOVA with genotype as independent factor and stimuli/trials as repeated-measure factor (g, k, n). *p < 0.05; **p < 0.01. WT EphB6^+/+ mice, KO EphB6^−/− mice, FMT fecal microbiota transplantation, PBS phosphate-buffered saline, PFC prefrontal cortex, PLP pyridoxal 5′-phosphate, VB6 vitamin B₆, Glu glutamic acid, GABA gamma-aminobutyric acid, Gly glycine, Asp aspartic acid, Ser serine, Gln glutamine, NE norepinephrine, EP epinephrine, DA dopamine, 5-HT 5-hydroxytryptamine, DOPAC dihydroxy-phenyl acetic acid, mPFC middle prefrontal cortex, VTA ventral tegmental area, Th tyrosine hydroxylase, ACSF artificial cerebrospinal fluid. Statistical values are presented in Additional file 3: Table S2