Rapid CommunicationDifferently shaped spines increase in the posterodorsal medial amygdala of oxytocin knockout female mice

•Oxytocin is an important synaptic modulator in the posterodorsal medial amygdala.•Oxytocin can modulate the number of differently shaped spines.•Oxytocin plays a crucial role in the regulation of female mice reproduction.

The posterodorsal medial amygdala (MePD) is a sexually dimorphic area in the social behavior neural network, with high concentration of oxytocin (OT) receptors. Wild type (WT) and OT knockout (OTKO) females were studied in proestrus, and Golgi-impregnated spines in the MePD were classified. Results show that the OTKO group has increased density of thin, mushroom, and stubby/wide spines when compared to the WT (p < 0.01 in all cases). These data indicate that OT is an important synaptic modulator in the MePD, a finding that is likely involved with the display of the female sexual behavior.