title: Ontogenetic studies on the topographical heterogeneity of somatostatin-containing neurons in rat hypothalamus.
abstract: The ontogeny of the somatostatin-containing neuron system was investigated by light-microscopic immunohistochemistry. During development, immunoreactive somatostatin-containing neurons arise from three discrete regions of the neuroepithelium of the third ventricle and show a chronological difference. The neurons are first evident within the third ventricle floor on day 12.5 of gestation; they move thereafter to the arcuate nucleus. The second generation occurs in the dorsal region of the arcuate nucleus during days 17.5-19.5; these neurons migrate sequentially into the arcuate-ventromedial nuclear region. The third generation is recognized in the neuroepithelial cell layer of the rostral hypothalamus on day 17.5 of gestation; these cells move to the periventricular area. This latter generation is most prominent during days 3-6 after birth, and some of the cells are seen sporadically even up to day 20. The first two generations give rise to the somatostatin neuron system in the arcuate-ventromedial nuclear region, while the latter gives rise to that in the rostral periventricular region in the adult rat hypothalamus.
mesh_terms: D000818:Animals; D005260:Female; D006651:Histocytochemistry; D007031:Hypothalamus / Q000032:analysis / Q000196:embryology*; D007124:Immunoenzyme Techniques; D008297:Male; D009474:Neurons / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000276:immunology*
chemical_list: D013004:Somatostatin