Interneurons targeting similar layers receive synaptic inputs with similar kinetics.
GABAergic interneurons play diverse and important roles in controlling neuronal network dynamics. They are characterized by an extreme heterogeneity morphologically, neurochemically, and physiologically, but a functionally relevant classification is still lacking. Present taxonomy is essentially based on their postsynaptic targets, but a physiological counterpart to this classification has not yet been determined. Using a quantitative analysis based on multidimensional clustering of morphological and physiological variables, we now demonstrate a strong correlation between the kinetics of glutamate and GABA miniature synaptic currents received by CA1 hippocampal interneurons and the laminar distribution of their axons: neurons that project to the same layer(s) receive synaptic inputs with similar kinetics distributions. In contrast, the kinetics distributions of GABAergic and glutamatergic synaptic events received by a given interneuron do not depend upon its somatic location or dendritic arborization. Although the mechanisms responsible for this unexpected observation are still unclear, our results suggest that interneurons may be programmed to receive synaptic currents with specific temporal dynamics depending on their targets and the local networks in which they operate.
Cossart
Rosa
R
INMED, INSERM U29, Parc scientifique de Luminy, B.P 13, 13673 Marseille, Cédex 9, France.
Petanjek
Zdravko
Z
Dumitriu
Dani
D
Hirsch
June C
JC
Ben-Ari
Yehezkel
Y
Esclapez
Monique
M
Bernard
Christophe
C
D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D048430:Cell Shape / Q000502:physiology; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018756:GABA Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007395:Interneurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009415:Nerve Net / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D018377:Neurotransmitter Agents; D011963:Receptors, GABA-A; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid