Abstract

• The distribution of serotonin-2 receptors in the rat brain was studied by light microscopic autoradiography, using [³H]ketanserin as a ligand. The serotonin-2 receptor densities were quantified by an actual count of labeled silver grains from the tissue preparations. A heterogeneous distribution of serotonin-2 receptor densities was found in the rat brain. High concentrations of serotonin-2 receptors were localized over the superior colliculus, neostriatum, amygdaloid complex and mammillary body. Intermediate concentrations were found over the dentate gyrus and visual cortex(area 17). Low densities were found over the substantia nigra and olfactory tubercie. The observations made in this study indicate that the anatomical distribution of serotonin-2 receptor is in accord with the distribution of serotoninergic innervation and the densities of serotonin-2 preceptor are differences in brain area of rat.