Developing Brain as a Giant Multipotent Endocrine Gland

摘要: The brain of adult mammals is composed neuronal ensembles, which are intergrated in the course synaptic transmission by chemical signals (CSs). Among them, there classical neurotransmitters, neuropeptides, etc. In addition, neurosecretory neurons secrete same CSs to blood vessels areas lacking blood-brain barrier (BBB), though their spectrum greatly limited. According conventional conception, lacks neuroendocrine function over ontogenetic period lasting from genesis units development neuron-to-neuron connections (synaptogenesis) and BBB. Nevertheless, some recent data contradict this concept making reasonable its that receptors expressed just after origin long before establishment During period, considered diffusive inductors development, provide paracrine regulation differentiation. Although beyond doubt, do not agree with concept. For example, transiently many developing brain, no sources respective close vicinity. This might be explained CS transfer synthesizing toward target via circulation, i.e., due autoregulation. our hypothesis, serve as endocrine cells, can a giant multipotent gland providing itself peripheral organs preceding synaptogenesis term “giant multipotent” means brain-derived circulating occupancy at periphery organism should exceed those adulthood. Gonadotropin-releasing hormone (GnRH)-producing dopaminergic neurons, most representative populations peptidergic monoaminergic were used for testing hypothesis. age dynamics GnRH dopamine (DA) general circulation rats, concentrations these agents sufficiently great cells BBB, but they dropped an undetectable level BBB appearance. Furthermore, microsurgical lesion DA-ergic resulted dramatic drop both blood, confirming principal only source CSs. Potential targets CSs, including DA, cells. gonads begin express simultaneously onset synthesis fetal rats. DA-sensitive are, e.g., represented suprachiasmatic nucleus epithelial kidney. Both cell types D2 related fall DA. Thus, differentiating play roles secretory gland, respectively, interneuronal maturation