[Morphometric studies of the visual system of the rat following elimination of noradrenergic afferent pathways with 6-hydroxydopamine].

The cell density and the cell size were investigated in the dorsal lateral geniculate body (d lgn) and in the visual cortex (V.C.) of 6-hydroxydopamine (6-OHDA) treated rats and compared with control-rats. Following i. p. administration of 6-OHDA at the first postnatal day no catecholaminergic fibres were present in the d lgn and V.C. on 21st postnatal day. The results of the morphometric investigations have shown an increased cell size and cell density in the medial and caudal part of the d lgn. In the visual cortex cell size is decreased in nearly all laminae. The cell density in the V.C. increased in the laminae II, IV, VIb and c and decreased in the lamina VIa. The possible trophic or regulatory influences of the noradrenergic system on cell size and cell density is discussed.