Oxytocin excites neurones in the bed nucleus of the stria terminalis of the lactating rat in vitro.

Unit recordings were made in the bed nucleus of the stria terminalis in brain slices obtained from lactating rats. Addition of 10(-8) to 10(-6) M oxytocin to the perfusate caused a reversible and repeatable excitation in 28/53 (53%) of neurones. The excitatory effect of oxytocin was completely blocked in the presence of the antagonist [d(CH2)5,D-Tyr(OEt)2,Val4,Cit8]vasopressin (5 x 10(-7) M) and a smaller excitation was achieved with equimolar concentration of arginine vasopressin, implicating the involvement of an oxytocin receptor. This effect is discussed in relation to the actions of centrally administered oxytocin in the lactating rat.