title: The distribution of neuropeptide Y-like immunoreactive neurons in the human medulla oblongata.
abstract: We have described the distribution of neuropeptide Y-like immunoreactive neurons in the medulla oblongata of the adult human. The majority of neuropeptide Y-like immunoreactive cells were found in four regions of the medulla: the ventrolateral reticular formation, the dorsomedial medulla, the secondary sensory nuclei and the rostral raphe nuclei. The morphology of neuropeptide Y-like immunoreactive cells varied in each of these regions. In the ventrolateral reticular formation, the labelled neurons were round and pigmented caudal to the obex but elongated and non-pigmented rostral to the obex; in the dorsomedial medulla, they were triangular and pigmented caudal to but not rostral to the obex; in the secondary sensory nuclei, they were multipolar, non-pigmented and significantly smaller than in the other areas; in the rostral raphe nuclei, they were bipolar and non-pigmented. Colocalization studies revealed that many neuropeptide Y-like immunoreactive cells also synthesize monoamines, consistent with conclusions based on a quantitative comparison of their distributions. Neuropeptide Y-like immunoreactivity was present in about 25% of presumed noradrenaline-synthesizing cells in the caudal ventrolateral medulla (corresponding to the A1 region); about 50% of adrenaline- and 70% of presumed serotonin-synthesizing cells in the rostral ventrolateral medulla (C1 and B2-3 regions); 90-100% of presumed noradrenaline-synthesizing cells in the dorsomedial medulla at and above the obex (A2 region); about 50% of adrenaline-synthesizing cells in the rostral dorsomedial medulla (C2 region); about 5% of presumed serotonin-synthesizing cells in the rostral raphe nuclei (B2-3 region). The largest of these groups was the presumed serotonin-synthesizing cells that contained neuropeptide Y-like immunoreactivity in the rostral ventrolateral medulla. This is the first report of such a cell group in the medulla of any mammal, and emphasizes the neuroanatomical differences between humans and other species.
mesh_terms: D000368:Aged; D001931:Brain Mapping; D002395:Catecholamines / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000032:analysis* / Q000166:cytology; D009478:Neuropeptide Y / Q000032:analysis*; D010651:Phenylalanine Hydroxylase / Q000032:analysis; D010625:Phenylethanolamine N-Methyltransferase / Q000032:analysis; D012701:Serotonin / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
chemical_list: D002395:Catecholamines; D009478:Neuropeptide Y; D012701:Serotonin; D010651:Phenylalanine Hydroxylase; D014446:Tyrosine 3-Monooxygenase; D010625:Phenylethanolamine N-Methyltransferase