title: In vitro and in vivo physiology of low nanomolar concentrations of Zn2+in artificial cerebrospinal fluid.
abstract: Artificial cerebrospinal fluid (ACSF), i.e., brain extracellular medium, which includes Ca2+and Mg2+, but not other divalent cations such as Zn2+, has been used for in vitro and in vivo experiments. The present study deals with the physiological significance of extracellular Zn2+in ACSF. Spontaneous presynaptic activity is suppressed in the stratum lucidum of brain slices from young rats bathed in ACSF containing 10 nM ZnCl2, indicating that extracellular Zn2+modifies hippocampal presynaptic activity. To examine the in vivo action of 10 nM ZnCl2on long-term potentiation (LTP), the recording region was perfused using a recording electrode attached to a microdialysis probe. The magnitude of LTP was not modified in young rats by perfusion with ACSF containing 10 nM ZnCl2, compared to perfusion with ACSF without Zn2+, but attenuated by perfusion with ACSF containing 100 nM ZnCl2. Interestingly, the magnitude of LTP was not modified in aged rats even by perfusion with ACSF containing 100 nM ZnCl2, but enhanced by perfusion with ACSF containing 10 mM CaEDTA, an extracellular Zn2+chelator. The present study indicates that the basal levels of extracellular Zn2+, which are in the range of low nanomolar concentrations, are critical for synaptic activity and perhaps increased age-dependently.
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
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52- 1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Nishio
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52- 1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Yukina
authors.initials: Y
authors.lastname: Shakushi
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52- 1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Miku
authors.initials: M
authors.lastname: Sasaki
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: Osawa
authors.affiliation: Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52- 1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takeda
mesh_terms: D000818:Animals; D056654:CA3 Region, Hippocampal / Q000187:drug effects / Q000502:physiology*; D002555:Cerebrospinal Fluid; D002712:Chlorides / Q000494:pharmacology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D055366:Synaptic Potentials / Q000187:drug effects; D015032:Zinc / Q000378:metabolism* / Q000494:pharmacology; D017967:Zinc Compounds / Q000494:pharmacology*
chemical_list: D002712:Chlorides; D017967:Zinc Compounds; C016837:zinc chloride; D015032:Zinc