title: Neuronal colocalization of adenosine deaminase, monoamine oxidase, galanin and 5-hydroxytryptophan uptake in the tuberomammillary nucleus of the rat.
abstract: Neurons of the tuberomammillary nucleus (TM) in the rat have previously been shown to contain the enzymes adenosine deaminase (ADA), histidine decarboxylase (HDC) and glutamate decarboxylase (GAD). Some neurons coextensive with this cell group also exhibit immunoreactivity for the neuropeptide galanin, express monoamine oxidase activity (MAO), or display the ability to accumulate and decarboxylate 5-hydroxytryptophan (5-HTP). Histochemical and immunohistochemical techniques were used to determine the extent to which these neurochemical properties are colocalized in neurons immunoreactive for adenosine deaminase. Galanin was found to coexist with ADA in about 45% of the neurons in the TM. In addition, a large number of cells immunoreactive for galanin alone were observed in the posterior hypothalamus outside the confines of TM. Neurons displaying MAO activity formed a subpopulation of those immunoreactive for ADA; all neurons containing MAO also contained ADA whereas only 60% of the ADA-immunoreactive cells were reactive for MAO. Approximately 20% of ADA-immunoreactive neurons represented nearly all cells having 5-HTP uptake capability. However, a very few cells in TM showing 5-HTP uptake capability appeared to be devoid of ADA immunoreactivity. These results demonstrate that although neurons of TM are homogeneous with respect to a number of possible neurotransmitters markers and associated enzymes, these neurons are heterogeneous with respect to their expression of galanin, MAO and 5-HTP uptake. In certain respects the segregation of histochemical properties within TM correlates with previous histochemical work by others, and suggests the possibility of functional diversity of TM.
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism*; D000243:Adenosine Deaminase / Q000032:analysis*; D000818:Animals; D005455:Fluorescent Antibody Technique; D019004:Galanin; D006651:Histocytochemistry; D007031:Hypothalamus / Q000032:analysis* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D008995:Monoamine Oxidase / Q000032:analysis*; D009700:Nucleoside Deaminases / Q000032:analysis*; D010455:Peptides / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D010455:Peptides; D019004:Galanin; D006916:5-Hydroxytryptophan; D008995:Monoamine Oxidase; D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase