The hypothalamic arcuate nucleus of rat—A quantitative golgi analysis

摘要: The hypothalamic arcuate nuclei of several hundred rats were studied with types Golgi impregnations in young and adult animals. In addition to qualitative observations, a computer-assisted quantitative analysis dendritic arbors axonal trajectories coronal horizontal sections was performed on 1,702 neurons rats. With data large numbers neurons, using product-moment trees, we found statistically reliable differences the mean size, shape, center mass, skewness, orientation trees different parts nucleus. Despite within nucleus, nucleus characterized as group from ventromedial nucleus. Generally two or three, but sometimes one four, primary dendrites arise somata total tree is usually fairly small. Some are covered spines, while others appear have smooth surfaces. Medially located often oriented dorsoventral direction, more lateral cells, especially at ventral surface hypothalamus, mediolaterally arbors; graded transition occurs between extremes. Dendrites originating may enter cellpoor zone therefore share afferents projecting into cell-poor zone. mass for all situated lateral, and, most areas, cell body. Dendritic fields tend be elongated; if an elliptical shape fitted analysis, major axis ellipse four five times greater than minor axis. generally rostrocaudal direction; this less pronounced laterally medially. Near third ventricle plane, run orthogonal tanycytes; tanycytes, scanning electron microscopy, constitute percentage tissue volume Tanycyte distal processes very orderly progression through nucleus. Axons originate either perikaryon proximal dendrite. axons arising also terminate Axons origin bifurcate, branch leaving other terminating it. entering median eminence likely divide collaterals rather before trajectory single thick dorsal. medial sections, intrinsic direction. Taken together, present study indicate regional variation structure complex level internal organization