Identified sources and targets of slow inhibition in the neocortex.
There are two types of inhibitory postsynaptic potentials in the cerebral cortex. Fast inhibition is mediated by ionotropic gamma-aminobutyric acid type A (GABA(A)) receptors, and slow inhibition is due to metabotropic GABA(B) receptors. Several neuron classes elicit inhibitory postsynaptic potentials through GABA(A) receptors, but possible distinct sources of slow inhibition remain unknown. We identified a class of GABAergic interneurons, the neurogliaform cells, that, in contrast to other GABA-releasing cells, elicited combined GABA(A) and GABA(B) receptor-mediated responses with single action potentials and that predominantly targeted the dendritic spines of pyramidal neurons. Slow inhibition evoked by a distinct interneuron in spatially restricted postsynaptic compartments could locally and selectively modulate cortical excitability.
Tamás
Gábor
G
Department of Comparative Physiology, University of Szeged, Közép fasor 52, Szeged H-6726, Hungary. gtamas@bio.u-szeged.hu
Lorincz
Andrea
A
Simon
Andrea
A
Szabadics
János
J
D000200:Action Potentials; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003712:Dendrites / Q000502:physiology; D005071:Evoked Potentials; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D007395:Interneurons / Q000502:physiology* / Q000648:ultrastructure; D019579:Neocortex / Q000166:cytology / Q000502:physiology*; D009433:Neural Inhibition; D009943:Organophosphorus Compounds / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology*; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000502:physiology; D018080:Receptors, GABA-B / Q000502:physiology; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure; D009435:Synaptic Transmission
D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D009943:Organophosphorus Compounds; D011724:Pyridazines; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; C066430:CGP 35348; C049853:gabazine; D001640:Bicuculline