Target-dependent use of co-released inhibitory transmitters at central synapses.
Corelease of GABA and glycine by mixed neurons is a prevalent mode of inhibitory transmission in the vertebrate hindbrain. However, little is known of the functional organization of mixed inhibitory networks. Golgi cells, the main inhibitory interneurons of the cerebellar granular layer, have been shown to contain GABA and glycine. We show here that, in the vestibulocerebellum, Golgi cells contact both granule cells and unipolar brush cells, which are excitatory relay interneurons for vestibular afferences. Whereas IPSCs in granule cells are mediated by GABA(A) receptors only, Golgi cell inhibition of unipolar brush cells is dominated by glycinergic currents. We further demonstrate that a single Golgi cell can perform pure GABAergic inhibition of granule cells and pure glycinergic inhibition of unipolar brush cells. This specialization results from the differential expression of GABA(A) and glycine receptors by target cells and not from a segregation of GABA and glycine in presynaptic terminals. Thus, postsynaptic selection of coreleased fast transmitters is used in the CNS to increase the diversity of individual neuronal outputs and achieve target-specific signaling in mixed inhibitory networks.
Dugué
Guillaume P
GP
Laboratoire de Neurobiologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8544, Ecole Normale Supérieure, 75005 Paris, France.
Dumoulin
Andréa
A
Triller
Antoine
A
Dieudonné
Stéphane
S
D000200:Action Potentials; D000818:Animals; D002525:Cerebellar Cortex / Q000166:cytology*; D005071:Evoked Potentials / Q000502:physiology; D058787:GABA-A Receptor Antagonists; D005998:Glycine / Q000378:metabolism*; D007395:Interneurons / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008959:Models, Neurological; D018408:Patch-Clamp Techniques; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000032:analysis; D018009:Receptors, Glycine / Q000032:analysis / Q000037:antagonists & inhibitors; D013331:Strychnine / Q000494:pharmacology; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D058787:GABA-A Receptor Antagonists; D011724:Pyridazines; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D005680:gamma-Aminobutyric Acid; C049853:gabazine; D013331:Strychnine; D005998:Glycine