Nicotinic antagonist alpha-bungarotoxin binding to rat hippocampal neurons containing nitric oxide synthase.
The hippocampus is a major target of alpha-bungarotoxin (alpha-BTX) binding. This ligand binds to the alpha 7 nicotinic, cholinergic receptor, which has been implicated in hippocampal habituation to repetitive auditory stimulation, a phenomenon thought to involve inhibitory neurons. This study examined whether alpha-BTX binds to neurons containing nitric oxide synthase (NOS), a marker of one subgroup of inhibitory hippocampal neurons. Rat hippocampal sections were processed for NOS immunohistochemistry, photographed and then processed for [125I]alpha-BTX autoradiography. Comparison between the distribution of neurons immunoreactive for NOS and those positive for alpha-BTX binding in the same regions of the hippocampal formation revealed a variable degree of colocalization of NOS and alpha-BTX. Of the cells labeled with alpha-BTX, 2% in the dentate gyrus and 40% in the hippocampus proper were also immunoreactive for NOS. These NOS/alpha-BTX neurons were most prevalent in CA1 stratum oriens. The results suggest a possible role for NOS-containing neurons in alpha 7-mediated inhibition to repetitive auditory stimulation in rat hippocampus.
Adams
C E
CE
Department of Psychiatry, University of Colorado Health Sciences, Denver 80262, USA.
Freedman
R
R
D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism / Q000494:pharmacology*; D018891:Dentate Gyrus / Q000166:cytology*; D007457:Iodine Radioisotopes; D009474:Neurons / Q000737:chemistry* / Q000201:enzymology; D018733:Nicotinic Antagonists / Q000378:metabolism / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000032:analysis
D002038:Bungarotoxins; D007457:Iodine Radioisotopes; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D019001:Nitric Oxide Synthase