Genetic pathways in the developmental specification of hypothalamic neuropeptide and midbrain catecholamine systems

The neuropeptide concept concerns the diverse and broad physiological funct ions of neuropeptides in behavioral adaptation. Neuropeptides like vasopres sin and corticotropin-releasing hormone can coordinate multiple brain funct ions due to the anatomical organization of the neurons producing them. The cell bodies are focally positioned in the hypothalamus and send long-reachi ng efferents to limbic and brainstem areas. Likewise, midbrain dopamine sys tems coordinate emotional behaviors and movement control by specific connec tivity of neurons in the midbrain to limbic and striatal centers, respectiv ely. The fundament of the functions of these signalling molecules is laid o ut during development when transmitter identity and connectivity are specif ied. This is a highly controlled process involving multiple transcription f actors and growth factors acting together in genetic pathways. Here, the ge netic pathways enrolling in developing vasopressin, corticotropin-releasing hormone, and midbrain dopamine neurons are discussed. (C) 2000 Elsevier Sc ience B.V. All rights reserved.