Oxytocin increases locus coeruleus alpha 2-adrenoreceptor responsiveness in rats

Oxytocin induces several antistress-like effects in rats. As the central noradrenergic nucleus locus coeruleus (LC) participates in arousal reactions and cardiovascular control, we used extracellular single-cell recording techniques to investigate a potential influence of oxytocin on LC neuronal activity. Oxytocin (1 mg/kg s.c.) given once a day for 5 days to male rats, increased the responsiveness of noradrenergic LC neurons to intravenous (i.v.) administration of clonidine, when compared to controls treated with saline for 5 days (P < 0.01). The spontaneous firing rate was not affected by oxytocin treatment. This study indicates that oxytocin treatment increases the responsiveness of LC alpha 2-adrenoreceptors.