Effect of adenosine on short-term synaptic plasticity in mouse piriform cortex in vitro: adenosine acts as a high-pass filter.
Physiol Rep. 2019-02-01; 7(3): e13992
DOI: 10.14814/phy2.13992
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Perrier SP(1), Gleizes M(1), Fonta C(1), Nowak LG(1).
Author information:
(1)CerCo, Université Toulouse 3, CNRS, Toulouse Cedex, France.
We examined the effect of adenosine and of adenosine A1 receptor blockage on
short-term synaptic plasticity in slices of adult mouse anterior piriform cortex
maintained in vitro in an in vivo-like ACSF. Extracellular recording of
postsynaptic responses was performed in layer 1a while repeated electrical
stimulation (5-pulse-trains, frequency between 3.125 and 100 Hz) was applied to
the lateral olfactory tract. Our stimulation protocol was aimed at covering the
frequency range of oscillatory activities observed in the olfactory bulb in vivo.
In control condition, postsynaptic response amplitude showed a large enhancement
for stimulation frequencies in the beta and gamma frequency range. A
phenomenological model of short-term synaptic plasticity fitted to the data
suggests that this frequency-dependent enhancement can be explained by the
interplay between a short-term facilitation mechanism and two short-term
depression mechanisms, with fast and slow recovery time constants. In the
presence of adenosine, response amplitude evoked by low-frequency stimulation
decreased in a dose-dependent manner (IC50 = 70 μmol/L). Yet short-term
plasticity became more dominated by facilitation and less influenced by
depression. Both changes compensated for the initial decrease in response
amplitude in a way that depended on stimulation frequency: compensation was
strongest at high frequency, up to restoring response amplitudes to values
similar to those measured in control condition. The model suggested that the main
effects of adenosine were to decrease neurotransmitter release probability and to
attenuate short-term depression mechanisms. Overall, these results suggest that
adenosine does not merely inhibit neuronal activity but acts in a more subtle,
frequency-dependent manner.
© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on
behalf of The Physiological Society and the American Physiological Society.