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Acting locally but sensing globally: impact of GABAergic synaptic plasticity on phasic and tonic inhibition in the thalamus
We have discovered that adult thalamocortical relay neurones exhibit a sustained enhancement of synaptic inhibition triggered by transient action potential firing of a single thalamic relay neurone. The sustained activity-dependent increase in IPSC frequency (+48.3 ± 11.4%, n = 32) was blocked by c...
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Published in: | The Journal of physiology 2008-11, Vol.586 (21), p.5091-5099 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We have discovered that adult thalamocortical relay neurones exhibit a sustained enhancement of synaptic inhibition triggered
by transient action potential firing of a single thalamic relay neurone. The sustained activity-dependent increase in IPSC
frequency (+48.3 ± 11.4%, n
= 32) was blocked by chelating calcium inside an individual cell, by scavenging nitric oxide or by blocking NMDA receptor
activation in the thalamus. Surprisingly, the tonic inhibition that is known to result from extrasynaptic GABA A receptor activation in these cells was unaffected by this local form of plasticity. However, tonic inhibition was increased
(+131.9 ± 56.5%, n
= 13) following widespread changes in GABA release across the thalamus. These data suggest that thalamocortical sleep-state
oscillations requiring membrane hyperpolarization will be influenced by global sensing of GABA release acting through extrasynaptic
GABA A receptors. In contrast, local changes in GABA release of the type observed following this novel form of activity-dependent
plasticity will influence local integration of sensory information without changing levels of tonic inhibition. |
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ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2008.158576 |