| The paraventricular nucleus (PVH) is a small bilateral group of neurons in the basal hypothalamus. PVH is a key brain structure in control of eating, drinking, response to stress, and other goal-oriented behaviors essential for life. Endocrine function is controlled directly by PVH neurons---via hypophysiotropic signaling molecules released into the blood from their axon terminals in the posterior pituitary and median eminence (pituitary stalk).; This work comprises a detailed "new millennium view" of spatial distribution of neuroendocrine effector cells within PVH, at much higher resolution than previously available. The major new finding is that primary neuroendocrine cell types are more intermixed within PVH subdivisions, and more widely distributed throughout the nucleus, than previously appreciated. Distribution patterns for a great number of intermixed non-neuroendocrine cells of hypophysiotropic chemical phenotype were also documented.; In a secondary project, a serial section anatomical atlas of PVH was constructed from Nissl sections of the rat brain originally used for L.W. Swanson's Brain Maps: an Anatomical Atlas of the Rat Brain. Thus, data can now potentially be recorded and interpreted at near serial section resolution within the context of a published standard. An accurate 3-D model of PVH and two new methods for analyzing high-resolution neuroanatomical data were developed from the serial section atlas. These in turn were used to elucidate important features of spatial distribution of neuroendocrine motoneurons in the paraventricular nucleus.; PVH cells were identified as neuroendocrine by fluorescent retrograde tracer (Fast Blue) in the blood. Neurons that contained the hormones vasopressin and oxytocin, and pituitary stimulating and inhibiting substances dopamine, somatostatin, corticotropin-releasing-hormone (CRH), thyrotropin-releasing-hormone (TRH) and growth hormone-releasing-hormone (GRH) were identified by antibody staining in (1-in-4, 15microm) series of frozen sections throughout rat PVH. All possible combinations of two different target proteins were stained in many series of sections from numerous animals, and identified with fluorescence microscopy. Maps of cell type distribution were collated (in register) within a graphics program. Detailed analysis of numbers, density, distribution and interrelationship between major neuroendocrine cell types in PVH from three exemplar animals is presented at high resolution, in a much more detailed view than previously available. |
