title: The tracing study of developing entorhino-hippocampal pathway.
abstract: The entorhino-hippocampal pathway is the major excitatory input from neurons of the entorhinal cortex on both ipsilateral and contralateral hippocampus/dentate gyrus. This fiber tract consists of the alvear path, the perforant path and a crossed commissural projection. In this study, the histogenesis and development of the various subsets of the entorhino-hippocampal projection have been investigated. DiI, DiO, Fast Blue tracing and calretinin immunocytochemistry as well as were carried out with pre and postnatal rats at different developmental stages. The alvear path and the commissural pathway start to develop as early as embryonic day E16, while the first perforant afferents reach the stratum lacunosum-moleculare of the hippocampus at E17 and at outer molecular layer of the denate gyrus at postnatal day 2. Retrograde tracing with DiI identifies entorhinal neurons in layer II-IV as the developmental origin of the entorhino-hippocampal pathway. Furthermore, calretinin immunocytochemistry revealed transitory Cajal-Retzius cells in the stratum lacunosum-moleculare of the hippocampus from E16. DiI labeling of entorhinal cortex fibers and combined calretinin-immunocytochemistry reveal a close relationship between Cajal-Retzius cells and entorhinal afferents. This temporal and spatial relationship suggests that Cajal-Retzius cell serves as a guiding cue for entorhinal afferents at early cortical development.
authors.affiliation: Institute of Neurobiology, Henan University, Kaifeng 475004, Henan Province, PR China. jinbo_deng@henu.edu.cn
authors.forename: Jin-Bo
authors.initials: JB
authors.lastname: Deng
authors.forename: Dong-Ming
authors.initials: DM
authors.lastname: Yu
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Ming-Shan
authors.initials: MS
authors.lastname: Li
mesh_terms: D000578:Amidines; D000596:Amino Acids; D000818:Animals; D000831:Animals, Newborn; D064032:Calbindin 2; D004622:Embryo, Mammalian; D018728:Entorhinal Cortex / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development; D005456:Fluorescent Dyes; D006624:Hippocampus / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development; D009434:Neural Pathways / Q000033:anatomy & histology / Q000196:embryology / Q000254:growth & development; D009474:Neurons / Q000502:physiology; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000378:metabolism
chemical_list: D000578:Amidines; D000596:Amino Acids; C576512:Calb2 protein, rat; D064032:Calbindin 2; D005456:Fluorescent Dyes; D064030:S100 Calcium Binding Protein G; C031455:diamidino compound 253-50; C098463:dolaisoleucine