Fig. 3

Focal application reveals d-serine sensitive nuclei. a Schematic of a medullary brainstem slice illustrating the sites of injection of d-serine and the extension of the labeled area when a bolus of aCSF containing 1% neutral red dye was pressure-ejected onto a specific locus. b–e Time course of changes in relative fR (ratio between fR at a given time and basal fR) induced by 10 s, 3 psi injections of 300 μM d-serine (red filled circles) and vehicle (aCSF pH 7.4, open circles) in specific brainstem nuclei. Injections of d-serine into the VRC (b) or the RN (c) increased the fR in neonatal medullary brainstem slices, but not when applied to the NTS (d) or the 5-SP (e). The yellow vertical bar indicates when a 10 s pulse was applied. Horizontal dashed line indicates no change. Symbols and vertical lines, mean and SEM, respectively (n = 7 for VRC, RN and NTS; n = 6 for 5-SP). The mixed ANOVA F-ratio and P are indicated for each nucleus; *P < 0.05, **P < 0.01, ***P < 0.001 Bonferroni post hoc test. 5-SP spinal trigeminal nucleus, NTS nucleus tractus solitarius, RN raphe nucleus, RTN retrotrapezoid nucleus, VRC ventral respiratory column