Morphological studies on Mn-SOD, NOS and calcium binding proteins in the rat hippocampus.
The immunohistochemical localization of manganese superoxide dismutase (Mn-SOD), nitric oxide synthase (NOS) and calcium (Ca) binding proteins; calbindin-D28K (Calb) and parvalbumin (Parv), was investigated in the rat hippocampus by using a double immunostaining method and an enzyme histochemical staining method. These substances showed considerable regional immunoreactivities in the hippocampus. (1) Although Mn-SOD- and NOS-immunoreactive neurons showed a similar distribution, virtually all of the latter neurons had no or weak Mn-SOD immunoreactivity in all subfields. This finding suggests that NO-producing neurons are not directly associated with Mn-SOD scavenger system in the hippocampus. (2) The co-localization of NOS and Parv or Calb was rarely found throught the hippocampus. (3) Neurons which were intensely immunostained for Mn-SOD were frequently found to be Parv-immunoreactive non-pyramidal cells, or Calb-immunoreactive pyramidal and non-pyramidal cells. From the latter two findings, it is speculated that Ca buffering effects of Parv and Calb are required in Mn-SOD neurons, but not in NO-producing neurons. Since Parv- or Calb-containing non-pyramidal cells are known to be GABAergic, most if not all, Mn-SOD-containing non-pyramidal cells may be GABAergic inhibitory neurons in the rat hippocampus. On the other hand, NOS neurons are also known to belong to GABAergic non-pyramidal cells. Therefore, Mn-SOD and NOS neurons constitute two distinct subclasses of non-pyramidal inhibitory neurons in the hippocampus.
First Department of Anatomy, Osaka City University Medical School, Japan.
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Matsui
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Ohta
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Takagi
D000818:Animals; D064092:Calbindin 1; D064026:Calbindins; D006624:Hippocampus / Q000737:chemistry*; D007150:Immunohistochemistry; D008297:Male; D019001:Nitric Oxide Synthase / Q000032:analysis*; D010320:Parvalbumins / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000032:analysis*; D013482:Superoxide Dismutase / Q000032:analysis*
C576500:Calb1 protein, rat; D064092:Calbindin 1; D064026:Calbindins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase