title: Neuronal interactions between neuropeptide Y (NPY) and catecholaminergic systems in the rat arcuate nucleus as shown by dual immunocytochemistry.
abstract: Several recent studies have suggested interactions between catecholamine (CA) and neuropeptide Y (NPY) neuronal systems in the rat brain. In order to obtain morphological evidence for such CA/NPY interactions in the arcuate nucleus, we have used a double immunostaining procedure using an anti-tyrosine hydroxylase (TH) antiserum as a marker for catecholamine neurons and an anti-NPY antiserum. This double staining, where the first staining is silver-gold intensified, was detectable at both light and electron microscopic levels. In semi-thin sections, a substantial overlap and close proximity of TH-immunopositive neurons and NPY neuronal elements could be seen within the arcuate nucleus. At the electron microscopic level, direct appositions between TH- and NPY-immunoreactive structures could be detected. These appositions were of axosomatic, axodendritic or axoaxonic types without any synaptic membrane differentiation. Moreover, direct appositions between NPY-immunoreactive structures have also been observed. This morphological study showing appositions between TH and NPY neuronal systems suggest direct interactions between these two systems in the arcuate nucleus.
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000201:enzymology / Q000648:ultrastructure*; D002395:Catecholamines / Q000032:analysis*; D005260:Female; D006651:Histocytochemistry; D008854:Microscopy, Electron; D009474:Neurons / Q000201:enzymology / Q000648:ultrastructure*; D009478:Neuropeptide Y / Q000032:analysis*; D051381:Rats; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D009478:Neuropeptide Y; D014446:Tyrosine 3-Monooxygenase