title: Development of the sympathoadrenal system in the chick embryo: an immunocytochemical study with antibodies to pan-neuroendocrine markers, catecholamine-synthesizing enzymes, proprotein-processing enzymes, and neuropeptides.
abstract: BACKGROUND
  The adrenal chromaffin cells synthesize, store and secrete a complex mixture containing amines, structural proteins, enzymes, and neurohormonal polypeptides. Most of the studies dealing with the development of the avian sympathoadrenal system have been based on antibodies recognizing signal molecules like HNK-1, NC-1, and N-CAM.
  
  
  METHODS
  The development of the chick sympathoadrenal system was studied from 3 1/2 to 21 days of incubation, both morphologically and immunocytochemically, using antibodies to 17 separate antigens, including antibodies to pan-neuroendocrine markers, catecholamine synthesizing enzymes, proprotein-processing enzymes, and neuropeptides.
  
  
  RESULTS
  Some of the antigens studied were heavily expressed from the first days of development, e.g., chromogranin-A, chromogranin-B, Go protein-alpha subunit, tyrosine hydroxylase, and galanin, while for others a strong heterogeneity both in number of immunoreactive cells and intensity of immunostaining was recorded at the different stages, e.g., dopamine-beta-hydroxylase,, 7B2 protein, proprotein convertase 2, somatostatin, met-enkephalin, secretogranin II, proprotein convertase 3, neuropeptide Y, phenyl-N-methyl transferase, and neuron-specific enolase. The first immunoreactivities to appear at day 3 1/2 were those for HNK-1, tyrosine hydroxylase, chromogranin-A, and chromogranin-B. Except for HNK-1, immunoreactivity for all the remaining antigens showed a steady increase up to the hatching.
  
  
  CONCLUSIONS
  Three expression patterns were found, in the developmental adrenal-gland: defining early permanent markers (chromogranin-A, chromogranin-B, Go protein-alpha subunit, tyrosine hydroxylase, and galanin), others that show a progressively increased expression until the day 10 of development (dopamine-beta-hydroxylase, 7B2 protein, proprotein convertase 2, somatostatin, met-enkephalin), and late-appearing antigens (secretogranin II, proprotein convertase 3, neuropeptide Y, phenyl-N-methyl transferase, and neuron-specific enolase).
authors.affiliation: Department of Morphological Sciences, University of Granada, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Sánchez-Montesinos
authors.forename: J A
authors.initials: JA
authors.lastname: Mérida-Velasco
authors.forename: J
authors.initials: J
authors.lastname: Espín-Ferra
authors.forename: L
authors.initials: L
authors.lastname: Scopsi
mesh_terms: D000311:Adrenal Glands / Q000737:chemistry / Q000196:embryology*; D000313:Adrenal Medulla / Q000737:chemistry / Q000196:embryology; D000818:Animals; D000906:Antibodies / Q000032:analysis / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D002395:Catecholamines / Q000096:biosynthesis*; D002642:Chick Embryo; D002864:Chromogranins / Q000032:analysis; D007150:Immunohistochemistry; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009479:Neuropeptides / Q000032:analysis; D009490:Neurosecretory Systems / Q000196:embryology* / Q000502:physiology; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D013564:Sympathetic Nervous System / Q000737:chemistry / Q000196:embryology*
chemical_list: D000906:Antibodies; D015415:Biomarkers; D002395:Catecholamines; D002864:Chromogranins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010751:Phosphopyruvate Hydratase