Fig. 7
OXT increases activity of CA3 pyramidal neurons. a A schematic of the approach to label PVN-projecting OXT neurons by injection of CTB-555 into the hippocampal CA3 region and intraperitoneal injection of fluoro-gold (4% w/v in 100 μl saline). b Left panel, CA3 pyramidal neurons labeled by CTB-555 (red). Section was counterstained with DAPI (blue). Right panel, PVN neurons back-labeled from the hippocampal CA3 region. The CTB+ cell bodies (red) were found in the caudal portion of the PVN and colocalized OXT (green) and fluoro-gold (pink). The arrow indicates the site of injection. Data were replicated in four mice. Scale bars: left, 250 μm; right, 100 μm. c OXTR-containing CA3 pyramidal neuron was targeted for recording, filled with biocytin, and reacted with avidin-rhodamine. Scale bar: 20 μm. d, e Representative traces and summary data comparing OXT (1 μM)-induced membrane depolarization in hippocampal CA3 pyramidal neurons from WT and Oxtr −/− mice (WT, n = 8 neurons from 6 mice; Oxtr −/−, n = 10 neurons from 6 mice; *P < 0.05, unpaired two-tailed Student’s t test). f, g Representative traces and summary data comparing the effect of OXT (1 μM) on action potential firing responses elicited by depolarizing current injection in hippocampal CA3 pyramidal neurons from WT and Oxtr −/− mice (n = 10 neurons from 6 mice per genotype; **P < 0.01, paired two-tailed Student’s t test). h Representative micrographs showing the expression of ChR2-EYFP in the subgranular zone of the DG and stratum radiatum. Scale bars: 100 and 20 μm (rectangle amplification). i Summary graph showing the average amplitude of optically evoked EPSCs recorded in DGCs after application of gabazine (10 μM) and CNQX (20 μM) plus APV (50 μM) (n = 3 neurons). Data represent the mean ± s.e.m
