Sex-specific effects of social isolation stress and ketamine on hippocampal plasticity

•Social isolation stress and low doses of ketamine alter hippocampal plasticity differently between male and female rats.•In male rats, social isolation inhibits hippocampal long-term potentiation, an effect that was rescued by ketamine.•Females in Diestrus and Proestrus exhibited long-term potentiation (LTP) that was not affected by the stress history or ketamine.•Proestrus female rats showed increased LTP response at the highest ketamine dose.