title: Discrimination of striatopallidum and extended amygdala in the rat: a role for parvalbumin immunoreactive neurons?
abstract: Synaptic effects of parvalbumin-immunoreactive (-ir) interneurons (PVs) upon medium spiny neurons may be essential to neural processing in the striatum and, in effect, may serve as an additional feature distinguishing striatum from extended amygdala. The present immunohistochemical study in the rat was done to evaluate the distributions of PVs in the striatum and extended amygdala. Numerous PVs occupy all structures currently regarded as having a striatal composition, including the caudate-putamen, nucleus accumbens, and olfactory tubercle, as well as structures that receive outputs from these, including the globus pallidus, ventral pallidum, entopeduncular nucleus and substantia nigra reticulata. The morphologies of striatal PVs and their distribution were similar to what has been previously reported. In addition, we found that the density of larger neostriatal PVs with extensive and densely immunoreactive dendritic and local axonal arbors is greatest laterally, particularly in striatal districts with slight calbindin-ir, including the striatal patch compartment. In contrast to the situation in striatum, few PVs were observed in the central and medial divisions of the extended amygdala, including the bed nucleus of stria terminalis, interstitial nucleus of the posterior limb of the anterior commissure and central and medial nuclei of the amygdala, or in mesopontine, peribrachial and medullary structures that receive extended amygdala output. The paucity of PVs may be a characteristic feature distinguishing extended amygdala and its projection areas from striatopallidum, as well as the general character of neural processing that occurs in each.
authors.affiliation: Department of Anatomy and Neurobiology, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St Louis, MO 63104, USA. zahmds@slu.edu
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Zahm
authors.forename: Simona
authors.initials: S
authors.lastname: Grosu
authors.forename: Joi C
authors.initials: JC
authors.lastname: Irving
authors.forename: Evelyn A
authors.initials: EA
authors.lastname: Williams
mesh_terms: D000679:Amygdala / Q000033:anatomy & histology / Q000502:physiology*; D000818:Animals; D001933:Brain Stem / Q000502:physiology; D064026:Calbindins; D048429:Cell Size; D003342:Corpus Striatum / Q000033:anatomy & histology / Q000502:physiology*; D007150:Immunohistochemistry; D009474:Neurons / Q000502:physiology*; D010320:Parvalbumins / Q000378:metabolism*; D016548:Prosencephalon / Q000502:physiology; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000378:metabolism
chemical_list: D064026:Calbindins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G