title: Characteristic of Extracellular Zn2+Influx in the Middle-Aged Dentate Gyrus and Its Involvement in Attenuation of LTP.
abstract: An increased influx of extracellular Zn2+into neurons is a cause of cognitive decline. The influx of extracellular Zn2+into dentate granule cells was compared between young and middle-aged rats because of vulnerability of the dentate gyrus to aging. The influx of extracellular Zn2+into dentate granule cells was increased in middle-aged rats after injection of AMPA and high K+into the dentate gyrus, but not in young rats. Simultaneously, high K+-induced attenuation of LTP was observed in middle-aged rats, but not in young rats. The attenuation was rescued by co-injection of CaEDTA, an extracellular Zn2+chelator. Intracellular Zn2+in dentate granule cells was also increased in middle-aged slices with high K+, in which the increase in extracellular Zn2+was the same as young slices with high K+, suggesting that ability of extracellular Zn2+influx into dentate granule cells is greater in middle-aged rats. Furthermore, extracellular zinc concentration in the hippocampus was increased age-dependently. The present study suggests that the influx of extracellular Zn2+into dentate granule cells is more readily increased in middle-aged rats and that its increase is a cause of age-related attenuation of LTP in the dentate gyrus.
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan. takedaa@u-shizuoka-ken.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takeda
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Koike
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Osaw
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Haruna
authors.initials: H
authors.lastname: Tamano
mesh_terms: D000375:Aging / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D018891:Dentate Gyrus / Q000187:drug effects / Q000378:metabolism*; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D015032:Zinc / Q000378:metabolism* / Q000633:toxicity
chemical_list: D015032:Zinc
keywords: Aging; Cognitive decline; Dentate granule cell; LTP; Zinc