Adenosine-induced presynaptic inhibition of IPSCs and EPSCs in rat hypothalamic supraoptic nucleus neurones.

  1. The effects of adenosine on synaptic transmission in magnocellular neurosecretory cells were investigated using whole-cell patch-clamp recordings in acute rat hypothalamic slices that included the supraoptic nucleus. 2. Adenosine reversibly reduced the amplitude of evoked inhibitory (IPSCs) and excitatory (EPSCs) postsynaptic currents in a dose-dependent manner (IC50 approximately 10 microM for both types of current). 3. Depression of IPSCs and EPSCs by adenosine was reversed by the application of the A1 adenosine receptor antagonist 8-cyclopentyl-1, 3-dimethylxanthine (CPT; 10 microM). 4. When pairs of stimuli were given at short intervals, adenosine inhibitory action was always less effective on the second of the two responses than on the first, resulting in an increased paired-pulse facilitation and suggesting a presynaptic site of action. This observation was confirmed by analysis of spontaneous miniature synaptic currents whose frequency, but not amplitude or kinetics, was reversibly reduced by 100 microM adenosine. 5. CPT had no effect on synaptic responses evoked at a low frequency of stimulation (0.05-0.5 Hz), indicating the absence of tonic activation of A1 receptors under these recording conditions. However, CPT inhibited a time-dependent depression of both IPSCs and EPSCs induced during a 1 Hz train of stimuli. 6. Taken together, these results suggest that adenosine can be released within the supraoptic nucleus at a concentration sufficient to inhibit the release of GABA and glutamate via the activation of presynaptic A1 receptors. By its inhibitory feedback action on the major afferent inputs to oxytocin and vasopressin neurones, adenosine could optimally adjust electrical and secretory activities of hypothalamic magnocellular neurones.

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Additional Info

Field Value
Source ISSN: 0022-3751
Author Oliet, Stéphane, H.R., Poulain, Dominique A.
Maintainer CCSD
Last Updated November 11, 2026, 09:37 (UTC)
Created November 11, 2026, 09:37 (UTC)
Identifier inserm-00000066
Language en
contributor Neurobiologie morphofonctionnelle ; Université Bordeaux Segalen - Bordeaux 2-Institut François Magendie-IFR8-Institut National de la Santé et de la Recherche Médicale (INSERM)
creator Oliet, Stéphane, H.R.
date 1999-11-11T00:00:00
harvest_object_id 7719f70b-140c-46c1-bd98-447ec82d17b9
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-12-04T00:00:00
relation info:eu-repo/semantics/altIdentifier/pmid/10545146
set_spec type:ART