ISSN:
1352-8661
Keywords:
MR spectroscopy
;
19F-MR spectroscopy
;
calcium
;
zinc
;
glutamate
;
NMDA
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
,
Physics
Notes:
Abstract The19F-NMR calcium indicator 5FBAPTA has been used to measure changes in free intracellular calcium, [Ca2+],, in superfused guinea pig cerebral cortical slices. Increases in [Ca2+], have been observed with depolarization and the combined insult of hypoxia and hypoglycemia. These increases in [Ca2+]i, can be explained by the excitotoxic hypothesis which proposes a central role for the neurotransmitter glutamate and the NMDA receptor in cell death. We, therefore, investigated the effects of glutamate and NMDA directly on [Ca2+]i, in cerebral cortical slices with31P-NMR to monitor the energy state. In the presence of glutamate (±Mg) a new resonance was observed in the19F spectra and was attributed to the Zn-5FBAPTA complex. The zinc peak appears with or just following an increase in [Ca2+]i, and with a drop in PCr. Similar results were obtained on exposing the tissues to NMDA. Zinc has been reported to be enriched in various parts of the brain and have a multiplicity of possible roles. This is the first time zinc has been shown in actively metabolizing tissue. The observation that the zinc resonance does not appear with depolarization or hypoxia and hypoglycemia suggests that the mechanisms of damage in these latter insults are not solely attributable to the release of excitotoxins.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01705291
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