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Changes in hippocampal adenosine efflux, ATP levels, and synaptic transmission induced by increased temperature
Author(s) -
Masino Susan A.,
Latini Serena,
Bordoni Francesca,
Pedata Felicita,
Dunwiddie Thomas V.
Publication year - 2001
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.1060
Subject(s) - adenosine , hippocampal formation , neurotransmission , excitatory postsynaptic potential , efflux , chemistry , biophysics , neuroscience , extracellular , slice preparation , medicine , endocrinology , biology , electrophysiology , biochemistry , receptor
Abstract Previous studies have demonstrated that when the temperature of hippocampal brain slices is increased, there is a corresponding depression of synaptic potentials mediated by an increased activation of presynaptic adenosine A 1 receptors. The present experiments demonstrate that when the temperature of hippocampal slices is raised from 32.5°C to either 38.5°C or 40.0°C there is a marked, temperature‐dependent increase in the efflux of endogenous adenosine and a corresponding decrease in excitatory synaptic responses. The increase in efflux is rapidly reversible on lowering the slice temperature and the temperature‐induced efflux is repeatable. Control experiments suggest that this increased efflux of adenosine is not the result of hypoxia or ischemia secondary to a temperature‐induced increase in the metabolic rate of the slice. The increase in adenosine efflux was not accompanied by any significant change in the ATP levels in the brain slice, whereas a hypoxic stimulus sufficient to produce a comparable depression of excitatory transmission produced an ∼75% decrease in ATP levels. These experiments indicate that changes in brain slice temperature can alter purine metabolism in such a way as to increase the adenosine concentration in the extracellular space, as well as adenosine efflux from hippocampal slices, in the absence of significant changes in ATP levels. Synapse 41:58–64, 2001. © 2001 Wiley‐Liss, Inc.