title: Neurogenesis in the dentate gyrus of the rat hippocampus enhanced by tickling stimulation with positive emotion.
abstract: Hippocampal neurogenesis is influenced by many factors. In this study, we examined the effect of tactile stimulation (tickling), which induced positive emotion, on neurogenesis in the dentate gyrus (DG) of the hippocampus. Four week-old rats were tickled for 5 min/day on 5 consecutive days and received 5-bromo-2'-deoxyuridine (BrdU) administration for 4 days from the second tickling day. Then they were allowed to survive for 18 h or 3 weeks after the end of BrdU treatment. Neurogenesis in the DG was compared between the tickled and untickled rats by using immunohistochemistry with anti-BrdU antibody. The result showed that the number of BrdU- and NeuN (neural cell marker)-double positive neurons on 18h as well as 3 weeks of the survival periods was significantly increased in the tickled group as compared with the untickled group. The expression of mRNA of brain-derived neurotrophic factor (BDNF) in the hippocampus of the tickled rats was not altered when compared with the control rats. In conclusion, tickling stimulation which induces positive emotion may affect the generation and survival of new neurons of the DG through the BDNF-independent pathway.
authors.affiliation: Department of Diagnostic Biochemistry, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamamuro
authors.forename: Kouji
authors.initials: K
authors.lastname: Senzaki
authors.forename: Satomi
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Miyo
authors.initials: M
authors.lastname: Hori
authors.forename: Shigeko
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Murakami
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiga
authors.forename: Osamu
authors.initials: O
authors.lastname: Urayama
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis; D004644:Emotions / Q000502:physiology*; D006624:Hippocampus / Q000254:growth & development*; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D055495:Neurogenesis / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D019208:Brain-Derived Neurotrophic Factor