DEVELOPMENT OF PARVALBUMIN-IMMUNOREACTIVE NEURONS IN ORGANOTYPIC SLICE CULTURE
Noémi Sóki1, 2, Alexandra Stayer-Harci1, Bálint Balogh1, Melinda Boros1, 1, 2, Mónika Vecsernyés1, György Sétáló1, László Seress1, 2, Hajnalka Ábrahám1, 2
Organotypic slice culture is a widely used method to study mechanisms of drug effects and neural regeneration. Although hippocampal sclice culture can be maintained for several weeks, information about maturation of different cell types is incomplete. Therefore, we studied maturation of parvalbumin (PV)–immunoreactive neurons in organotypic hippocampal and entorhino-hippocampal tissue cultures of the rat. Difference between maturation of PV-immunoreactive cells in cultured slices and in perfused animals was also examined. Hippocampal and entorhino-hippocampal sclice culture were dissected from postnatal 8 days (P8) old rat, and cultures then were fixed at various times during a 3 weeks long culturing period. Transcardially perfused and fixed P8-29 rats were used as controls. PV immunohistochemistry was performed on cryostate sections and they were studied under a light microscope. PV-immunoreactive neurons were visible in Ammon’s horn at P8, and P10-12 in the dentate gyrus hippocampal and entorhino-hippocampal slices. Development of apical and basal dendrites of PV-positive interneurons was the fastest in perfused rats, while dendritic growth were retracted in entorhino-hippocampal as well as hippocampal slices. Perisomatoic PV-immunoreactivity indicating axon terminals of basket cells could be observed in Ammon’s horn of P10 old perfused animals, while perisomatic PV-immunoreactive terminals appeared at P12 in the entorhino-hippocampal and a few days later in hippocampal culture. Our results suggest that factors needed for dendritic and synaptic maturation of PV-immunoreactive neurons of Ammon’s horn are present in slice culture, and input from the entorhinal cortex support their development. Supported by: NAP 2.0 (2017-1.2.1-NKP-2017-00002), PTE EFOP-3.6.1.-16-2016-00004, 20765-3/2018/FEKUTSTRAT.