Structural plasticity of GABAergic axons is regulated by network activity and GABAA receptor activation
By A. Schuemann, Agnieszka Klawiter, Tobias Bonhoeffer, C. Wierenga. 2013
31 citations recorded by the source corpus.
Coordinated changes at excitatory and inhibitory synapses are essential for normal brain development and function. It is well established that excitatory neurons undergo structural changes, but our knowledge about inhibitory structural plasticity is rather scarce. Here we present a quantitative analysis of the dynamics of GABAergic boutons in the dendritic region of the hippocampal CA1 area using time-lapse two-photon imaging in organotypic hippocampal cultures from GAD65-GFP mice. We show that ~20% of inhibitory boutons are not stable. They are appearing, disappearing and reappearing at specific locations along the inhibitory axon and reflect immature or incomplete synapses. Furthermore, we observed that persistent boutons show large volume fluctuations over several hours, suggesting that presynaptic content of inhibitory synapses is not constant. Our data show that inhibitory boutons are highly dynamic structures and suggest that inhibitory axons are continuously probing potential locations for inhibitory synapse formation by redistributing presynaptic material along the axon. In addition, we found that neuronal activity affects the exploratory dynamics of inhibitory axons. Blocking network activity rapidly reduces the number of transient boutons, whereas enhancing activity reduces the number of persistent inhibitory boutons, possibly reflecting enhanced competition between boutons along the axon. The latter effect requires signaling through GABAA receptors. We propose that activity-dependent regulation of bouton dynamics contributes to inhibitory synaptic plasticity.
Subfields: Cellular and Molecular Neuroscience, Neurology
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In Cellular and Molecular Neuroscience
- Friedemann Zenke
- Robert Froemke
- Matthieu Gilson
- Henning Sprekeler
- Tim P. Vogels
- Wulfram Gerstner
- Surya Ganguli
- Laurenz Wiskott
In Neurology
Citations in the corpus
- Inhibitory synaptic plasticity: spike timing-dependence and putative network function (2013, background): “Interneuronal network synchrony has been explored for simpler networks of cells coupled by both inhibitory and electrical synapses (Chow and Kopell, 2000; Lewis and Rinzel, 2003; Kopell and Ermentrout, 2004; Pfeuty et al., 2005; Saraga et al., 2006).”