Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/12779
Title: Concentration dynamics of nitric oxide in rat hippocampal subregions evoked by stimulation of the NMDA glutamate receptor
Authors: Ledo, Ana 
Barbosa, Rui M. 
Gerhardt, Greg A. 
Cadenas, Enrique 
Laranjinha, João 
Keywords: Carbon fiber microelectrode; NO diffusional spread; hippocampus
Issue Date: 29-Nov-2005
Publisher: National Academy of Sciences
Citation: PNAS. 102:48 (2006) 17483-17488
Abstract: Nitric oxide (*NO) production in response to stimulation of the NMDA glutamate receptor is implicated not only in the synaptic plasticity in hippocampus but may also participate in excitotoxic cell death. Using *NO-selective microssensors inserted into the diffusional field of *NO in acute hippocampal slices, we describe the *NO concentration dynamics evoked by NMDA receptor activation and report profound differences along the trisynaptic loop of the hippocampus. We measured the oxygen gradient across the slice thickness and conclude that *NO measurements were performed at cell layers experiencing physiological oxygen tensions. Recordings performed at increasing distances from the point of NMDA receptor stimulation resulted in a progressive decrease of *NO signals, reaching undetectable levels for distances >400 microm, supporting the notion of a wide diffusional spread of endogenously generated *NO in the hippocampus. Neither a picoinjection nor a continuous perfusion of NMDA resulted in high steady-state *NO levels; rather all signals were transient, suggesting that cells are able to efficiently respond to high *NO concentrations (typically 200-400 nM) bringing it to very low nM levels; the claimed high micromolar *NO range achieved by excessive stimulation of NMDA receptor may have to be reevaluated. The distinct responses to NMDA receptor stimulation along the trysynaptic loop suggest a differential *NO activity and/or regulation among the hippocampal subregions. These findings may be relevant for the understanding of the role of *NO in physiologic mechanisms in the hippocampus and the differential sensitivity of the hippocampal subregions to NMDA receptor-dependent neurodegeneration
URI: http://hdl.handle.net/10316/12779
ISSN: 0027-8424
Rights: openAccess
Appears in Collections:FFUC- Artigos em Revistas Internacionais
FCTUC Ciências da Vida - Artigos em Revistas Internacionais

Files in This Item:
File Description SizeFormat
Concentration dynamics of nitric oxide in rat hippocampal subregions.pdf333.37 kBAdobe PDFView/Open
Show full item record

Page view(s)

189
checked on Sep 17, 2019

Download(s)

48
checked on Sep 17, 2019

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.