title: Ghrelin directly stimulates adult hippocampal neurogenesis: implications for learning and memory.
abstract: Adult hippocampal neurogenesis is important in mediating hippocampal-dependent learning and memory. Exogenous ghrelin is known to stimulate progenitor cell proliferation in the dentate gyrus of adult hippocampus. The aim of this study was to investigate the role of endogenous ghrelin in regulating the in vivo proliferation and differentiation of the newly generating cells in the adult hippocampus using ghrelin knockout (GKO) mice. Targeted deletion of ghrelin gene resulted in reduced numbers of progenitor cells in the subgranular zone (SGZ) of the hippocampus, while ghrelin treatment restored progenitor cell numbers to those of wild-type controls. We also found that not only the number of bromodeoxyuridine (BrdU)-positive cells but also the fraction of immature neurons and newly generated neurons were decreased in the GKO mice, which were increased by ghrelin replacement. Additionally, in the GKO mice, we observed impairment of memory performance in Y-maze task and novel object recognition test. However, these functional deficiencies were attenuated by ghrelin administration. These results suggest that ghrelin directly induces proliferation and differentiation of adult neural progenitor cells in the SGZ. Our data suggest ghrelin may be a plausible therapeutic potential to enhance learning and memory processes.
authors: Department of Pharmacology and Medical Research Center for Bioreaction to ROS and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul, Koera.
authors: Endan
authors: E
authors: Li
authors: Hyunju
authors: H
authors: Chung
authors: Yumi
authors: Y
authors: Kim
authors: Dong Hyun
authors: DH
authors: Kim
authors: Jong Hoon
authors: JH
authors: Ryu
authors: Takahiro
authors: T
authors: Sato
authors: Masayasu
authors: M
authors: Kojima
authors: Seungjoon
authors: S
authors: Park
mesh_terms: D053687:Adult Stem Cells / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D054439:Ghrelin / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D058953:Neural Stem Cells / Q000187:drug effects / Q000502:physiology; D055495:Neurogenesis / Q000187:drug effects / Q000235:genetics*
chemical_list: D054439:Ghrelin