title: Immunohistochemical study on the neuronal diversity and three-dimensional organization of the mouse entopeduncular nucleus.
abstract: The entopeduncular nucleus (EPN) is one of the major output nuclei of the basal ganglia in rodents. Previous studies have divided it into rostral and caudal halves, with the former containing somatostatin (SOM)-immunoreactive neurons and the latter dominated by parvalbumin (PV)-containing neurons, respectively. However, it is unclear whether this simple rostrocaudal segmentation is appropriate, and the possibility of the existence of other neuronal populations remains to be investigated. In this study the cytoarchitecture of the mouse EPN was analyzed immunohistochemically. Substance P (SP)-immunoreactivity determined the extent of the EPN, which was 800 μm-long along the rostrocaudal axis. PV-positive neurons were concentrated in the caudal two-thirds of this range. PV-negative neurons were abundant in the rostral half but were further located caudally around the PV neuron-rich core. PV(+)/SOM(-) and PV(-)/SOM(+) neurons constituted 28.6% and 45.7% of EPN neurons, respectively, whereas the remaining population (25.7%) exhibited neither immunoreactivity. Eleven percent of EPN neurons lacked immunoreactivity for glutamic acid decarboxylase, indicating their non-GABAergic nature. Three-dimensional reconstruction revealed that PV-rich/SP-poor core was surrounded by PV-poor/SP-rich shell region. Therefore, presumptive thalamus-targeting PV neurons are outnumbered by other populations, and the regional heterogeneity shown here might be related to functionally distinct pathways through the basal ganglia.
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Miyamoto
authors.affiliation: Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan. Electronic address: tfukuda@kumamoto-u.ac.jp.
authors.forename: Takaichi
authors.initials: T
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D001931:Brain Mapping; D002452:Cell Count; D020392:Entopeduncular Nucleus / Q000166:cytology*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D021621:Imaging, Three-Dimensional; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000145:classification* / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D013788:Thalamus / Q000166:cytology
chemical_list: D009419:Nerve Tissue Proteins; D010320:Parvalbumins; D013373:Substance P; D013004:Somatostatin; D005968:Glutamate Decarboxylase
keywords: Basal ganglia; Glutamic acid decarboxylase; Immunohistochemistry; Parvalbumin; Somatostatin; Substance P