Humoral mediation of the development of the mammalian nervous system.

The application of the new ideas advanced by modern neuroscience research, mainly those about the neuronal plasticity and the extrinsic influences able to modify the behaviour of the neuronal populations, to the ontogenetic evolution of the nervous system, have conducted to the elaboration of the concept of the humoral mediation of the brain development. Data sustaining this concept come from at least four areas of investigations, referring to the influences which the endocrine glands (thyroid, gonads, adrenals, hypophysis and pineal), neurotransmitters and the "growth factors" exert on the in vivo and in vitro development of the nervous system. These data are synthetically presented in the present paper, a special attention being paid to the pineal gland and its hormones, due to the personal research of the author in this field. All these researches support some fascinating hypotheses regarding the future of this extremely controversed field of the neuroscience, hypotheses that are presented in the final chapter of the paper.