title: Release of vesicular Zn2+ in a rat transient middle cerebral artery occlusion model.
abstract: In the brain, Zn(2+) is stored in synaptic vesicles of a subgroup of glutamatergic nerve terminals. Although it has been reported that this Zn(2+) is released upon the excitation of nerves in vitro, there has been little study of the release of Zn(2+) during ischemia in vivo. Here, using brain microdialysis, the release of vesicular Zn(2+) was investigated in vivo. When the vesicular Zn(2+) was released into the synaptic cleft by a depolarizing stimulation achieved by perfusion with Ringer's solution containing high K(+) (100mM KCl), a significant increase in the extracellular concentration of Zn(2+) could be detected by microdialysis. Then, we investigated the release of vesicular Zn(2+) in a rat transient middle cerebral artery occlusion model using microdialysis. Consequently, the extracellular Zn(2+) level in the cortex increased within 15 min of the start of occlusion and reached a peak at 30 min, which was about twice the basal level. After 30 min, it declined with time returning to the basal level 15 min after reperfusion, which was performed after 60 min of occlusion. The results suggest that vesicular Zn(2+) would be released into the synaptic cleft during brain ischemia in vivo.
authors.affiliation: Graduate School of Medicine and Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
authors.forename: Youji
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Iida
authors.forename: Jun
authors.initials: J
authors.lastname: Abe
authors.forename: Masaki
authors.initials: M
authors.lastname: Mifune
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Kasuya
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohta
authors.forename: Kazuo
authors.initials: K
authors.lastname: Igarashi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Saito
authors.forename: Hideo
authors.initials: H
authors.lastname: Saji
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism* / Q000473:pathology; D008297:Male; D017551:Microdialysis / Q000379:methods; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013054:Spectrophotometry, Atomic / Q000379:methods; D013997:Time Factors; D015032:Zinc / Q000378:metabolism*
chemical_list: D011189:Potassium Chloride; D015032:Zinc