Vasopressin and oxytocin do not influence early sensory processing but affect mood and activation in man

Effects of arginine-vasopressin (AVP) and oxytocin (OX) on brainstem and middle latency auditory-evoked potentials (BAEP and MAEP), reflecting early sensory processing within the specific auditory pathways and primary auditory cortex, were investigated. Additionally, subjects rated their feelings of activation and mood on an adjective check list (EWL). The experiments were undertaken in 12 healthy male volunteers, receiving either placebo, 0.15 IU AVP, 0.5 IU AVP or 0.5 IU OX as IV bolus injection according to a within-subject double-blind design. There were no consistent effects of AVP and OX on BAEPs and MAEPs. AVP decreased self-perceived deactivation, fatigue and arousal. Results do not suggest an effect of AVP and OX on early stages of sensory processing, but, consistent with previous studies, demonstrate changes towards increased (self-perceived) general activation following administration of these hormones.