OXYTOCIN INCREASES LOCUS-COERULEUS ALPHA-2-ADRENORECEPTOR RESPONSIVENESS IN RATS

Oxytocin induces several antistress-like effects in rats. As the centr al noradrenergic nucleus locus coeruleus (LC) participates in arousal reactions and cardiovascular control, we used extracellular single-cel l recording techniques to investigate a potential influence of oxytoci n on LC neuronal activity. Oxytocin (1 mg/kg s.c.) given once a day fo r 5 days to male rats, increased the responsiveness of noradrenergic L C neurons to intravenous (i.v.) administration of clonidine, when comp ared to controls treated with saline for 5 days (P < 0.01). The sponta neous firing rate was not affected by oxytocin treatment. This study i ndicates that oxytocin treatment increases the responsiveness of LC al pha 2-adrenoreceptors. (C) 1998 Elsevier Science Ireland Ltd. All righ ts reserved.