In vivo regulation of extracellular adenosine levels in the cerebral cortex by NMDA and muscarinic receptors.

@article{Pazzagli1994InVR,
  title={In vivo regulation of extracellular adenosine levels in the cerebral cortex by NMDA and muscarinic receptors.},
  author={Marta Pazzagli and Claudia Corsi and Serena Latini and Felicita Pedata and Giancarlo Pepeu},
  journal={European journal of pharmacology},
  year={1994},
  volume={254 3},
  pages={
          277-82
        }
}
The adenosine concentration in samples of perfusate was determined 24 h after implantation of microdialysis fibre in the cortex. High performance liquid chromatography coupled with a fluorometric detector was used. K+ (100 mM) depolarization was followed by a 2- to 4-fold increase in adenosine efflux. The addition of tetrodotoxin (1 microM) to the perfusate was followed by a decrease in spontaneous and K(+)-evoked adenosine efflux. The increase induced by high K+ was markedly inhibited by the… Expand
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References

SHOWING 1-10 OF 27 REFERENCES
Effect of K+ depolarization, tetrodotoxin, and NMDA receptor inhibition on extracellular adenosine levels in rat striatum.
TLDR
The findings indicate that the extracellular adenosine level is influenced by neuronal activity, and that under strong depolarizing conditions the increase in adenoine level involves NMDA receptor activation. Expand
Adenosine antagonists increase spontaneous and evoked transmitter release from neuronal cells in culture
TLDR
It is likely that 8-PT potentiates glutamate release in both systems by blocking the effect of endogenous adenosine on presynaptic A1 receptors. Expand
Release of endogenous adenosine and its metabolites by the activation of NMDA receptors in the rat hippocampus in vivo
TLDR
Perfusion with zero‐Ca2+ artificial cerebrospinal fluid attenuated the NMDA‐evoked release of adenosine only by 16% (not signficant) but depressed the K+‐ Evoked release by 62%, indicating that most of theNMDA‐EVoked release is directly receptor‐mediated, whereas a large component of the K-evokedRelease could be via the release of an excitatory amino acid acting at the NMda receptors. Expand
Extracellular levels of adenosine and its metabolites in the striatum of awake rats: inhibition of uptake and metabolism.
TLDR
The present results show that the microdialysis technique can be used to determine levels of purines in the extracellular fluid of defined brain regions in awake animals and that adenosine levels can be altered in vivo by inhibitors of adenoine transport and adenosines deaminase. Expand
Evidence that prejunctional adenosine receptors regulating acetylcholine release from rat hippocampal slices are linked to an N-ethylmaleimide-sensitive G-protein, but not to adenylate cyclase or dihydropyridine-sensitive Ca2+-channels.
TLDR
The results suggest that the presynaptic inhibitory effects of A1-receptor agonists on [3H]ACh release are exerted via a nucleotide-binding protein that can be inhibited by NEM. Expand
Adenosine decreases aspartate and glutamate release from rat hippocampal slices.
TLDR
The hypothesis that adenosine modulates the electrophysiological responses to stimulation of stratum radiatum through a reduction of the release of the excitatory amino acids aspartate and glutamate is supported. Expand
Adenosine and Glutamate Modulate Each Other's Release from Rat Hippocampal Synaptosomes
TLDR
The results suggest that, at least in synaptosomal preparations from rat hippocampus, adenosine and glutamate modulate each other's release, and the exact mechanism of such interplay could help in the understanding of excitatory amino acid neurotoxicity. Expand
Effect of adenosine, adenosine triphosphate, adenosine deaminase, dipyridamole and aminophylline on acetylcholine release from electrically-stimulated brain slices
TLDR
Adenosine, in concentrations ranging from 1 to 100 microM, reduced in a dose-dependent manner the release of acetylcholine and was more active on the stimulated than on the resting release, however, the fractional reduction by adenosine of stimulated release of ACh did not vary with increasing stimulation rate. Expand
Purine levels in the intact rat brain. Studies with an implanted perfused hollow fibre
TLDR
The free exchangable concentration of adenosine in the rat brain is likely to be 102 micro M, which is high enough to potentially affect central nervous function. Expand
Effect of Adenosine, Adenosine Derivatives, and Caffeine on Acetylcholine Release from Brain Synaptosomes: Interaction with Muscarinic Autoregulatory Mechanisms
Abstract: Synaptosomes, prepared from rat cerebral cortex and hippocampus, were preincubated with [methyl‐3H]choline. The effect of adenosine, cyclohexyl‐adenosine, N‐ethylcarboxamide adenosine,Expand
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