Fig. 1.

EphA receptor gene expression in the developing mouse raphe. A, qPCR of EphA3, EphA4, EphA5, EphA6, EphA7, and EphA8 mRNAs in DR extracts from P5 mice (n = 4 mice/experiment). Relative mRNA expression was calculated as 2^–ΔCt (delta of cycle threshold). Data are presented as mean ± SEM from three independent experiments. B, In situ hybridization of SERT, EphA3, EphA4, EphA5, and EphA7 mRNAs is shown at three different rostro-caudal levels of the raphe nuclei, including DR (B7), caudal DR (B6), rostral MnR (B8), caudal MnR (B5), raphe pallidus (B1), obscurus (B2), and magnus (B3). Coronal serial sections (20 μm thick) were labeled with the five different probes. Localization of 5-HT neurons as revealed by SERT expression was outlined with dashed yellow lines that were transferred to the consecutive sections on the series. This shows that only EphA5 labeling coincides clearly with the contours of B7 and B8. EphA4 and EphA7 are also strongly expressed in the brainstem, but signal is mainly detected in cell groups such as the anterior tegmental nucleus (atg), the dorsal tegmental nucleus (dtg), or the inferior olive (io) that come very close to the raphe. Scale bar = 250 μm.