title: Ultrastructural study of nitric oxide synthase-containing striatal neurons and their relationship with parvalbumin-containing neurons in rats.
abstract: Single- and double-label electron microscopic immunocytochemistry was used to examine the ultrastructure of striatal neurons containing nitric oxide synthase (NOS+) and evaluate the synaptic relationship of NOS+ striatal neurons with those containing parvalbumin (PV+). In both the single-label and double-label studies, NOS+ perikarya were observed to possess polylobulated nuclei. In the single-label studies, NOS+ terminals were seen forming synaptic contacts with dendritic shafts and dendritic spines that did not contain NOS, but not with NOS+ perikarya or dendrites. In the double-label studies (using diaminobenzidine and silver intensified immunogold as markers), nitric oxide synthase and parvalbumin immunoreactions were found in two different populations of medium-sized aspiny striatal neurons. The PV+ axon terminals were seen forming symmetric synapses on the dendritic spines of neurons devoid of PV or NOS labeling, on PV+ dendrites, and on NOS+ soma and dendrites. In contrast, NOS+ terminals were not observed to form synaptic contacts with the dendrites or soma of either PV+ or NOS+ neurons. These findings suggest that NOS+ striatal interneurons form synaptic contact with the spines and presumably the dendrites of striatal projection neurons, but not with the dendrites or soma of PV+ or NOS+ striatal interneurons. NOS+ neurons do, however, receive synaptic input from PV+ neurons.
authors.affiliation: Department of Neurology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Morello
authors.forename: A
authors.initials: A
authors.lastname: Reiner
authors.forename: G
authors.initials: G
authors.lastname: Sancesario
authors.forename: E J
authors.initials: EJ
authors.lastname: Karle
authors.forename: G
authors.initials: G
authors.lastname: Bernardi
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000166:cytology*; D007395:Interneurons / Q000737:chemistry* / Q000201:enzymology* / Q000648:ultrastructure; D008297:Male; D016253:Microscopy, Immunoelectron; D009433:Neural Inhibition / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000032:analysis*; D010320:Parvalbumins / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D016622:Silver Staining; D013569:Synapses / Q000737:chemistry / Q000648:ultrastructure; D016610:Tissue Embedding; D004124:p-Dimethylaminoazobenzene
chemical_list: D010320:Parvalbumins; D009569:Nitric Oxide; D004124:p-Dimethylaminoazobenzene; D019001:Nitric Oxide Synthase