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Subclass‐specific formation of perineuronal nets around parvalbumin‐expressing GABAergic neurons in Ammon's horn of the mouse hippocampus
Author(s) -
Yamada Jun,
Jinno Shozo
Publication year - 2015
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.23712
Subject(s) - parvalbumin , biology , perineuronal net , gabaergic , neuroscience , hippocampus , french horn , interneuron , subclass , anatomy , immunology , psychology , inhibitory postsynaptic potential , antibody , pedagogy
Perineuronal nets (PNNs) are closely associated with parvalbumin‐positive (PV+) neurons, and play a major role in controlling developmental neural plasticity. Considering the recent advances in classification of PV+ neurons, here we aimed to clarify whether PNNs might be associated with specific subclasses of PV+ neurons in the hippocampus. In this study, we labeled PNNs by Wisteria floribunda agglutinin (WFA), and classified PV+ neurons based on the combination of cellular location, molecular expression (neuropeptide Y [NPY], somatostatin [SOM], special AT‐rich sequence‐binding protein‐1 [SATB1]), and retrograde tracing through stereotaxic injection of Fluoro‐Gold (FG) into the medial septum. The criteria of each subclass can be summarized as follows: axo‐axonic cells, PV+/SATB1–/NPY– cells in the stratum pyramidale; basket cells, PV+/SATB1+/NPY– cells in the stratum pyramidale; bistratified cells, PV+/SATB1+/NPY+ cells in the stratum pyramidale; oriens‐lacunosum‐moleculare (O‐LM) cells, PV+/SOM+/FG– cells in the stratum oriens; hippocampo‐septal projection (H‐S) cells, and PV+/SOM+/FG+ cells in the stratum oriens. The ratios of formation of WFA+ PNNs around each subclass of PV+ neurons were estimated according to the optical disector principle. The vast majority (over 90%) of putative PV+ basket cells were surrounded by PNNs, while only a minor population (less than 10%) of putative PV+ axo‐axonic, O‐LM, and H‐S cells were enwrapped with PNNs. The ratios of formation of PNNs around putative PV+ bistratified cells were intermediate (25–50%). These findings indicate that PNNs may be specifically associated with PV+ basket cells, and also provide a key to understand the functional significance of PNNs and PV+ neurons in the hippocampus. J. Comp. Neurol. 523:790–804, 2015. © 2015 Wiley Periodicals, Inc.