[Maternal behavior. Induction of biological regulation in the animal]

The author assesses the current state of knowledge of the neuroendocrinological mechanisms in the induction of maternal behavior in animals in the immediate prepartum (nesting behavior) and in the post-partum, and of the mechanisms involved in the maintenance of this behavior (principally, feed-back from offsprings). Oxytocine (OT) appears very important for the induction of maternal behavior because of central targets of the parvocellular system of the hypothalamus. In fact, we have observed that parturition produces modifications in the RNAm of OT and of OT receptors: both in number and Bmax. An artificial induction of the behavior, outside parturition, is possible to a certain extent after a central, intra-cisternal, administration of OT. Other neuro-hormones have an important role: the modification of the balance of oestroprogestatives at the end of gestancy is absolutely necessary, vasopressin, endogeneous opioids which have a facilitatory effect, may be by an indirect stimulation of OT. Maternal behavior may also be artificially induced by a cervico-vaginal stimulation of a female virgin. Olfactive mechanisms are vital for behavioral specificity, which varies among different races. In primates, the developement of the neocortex is associated with the supremacy of social factors, but it is probable that similar neuroendocrinological mechanisms operate.