Cell type dependence and variability in the short-term plasticity of EPSCs in identified mouse hippocampal interneurones.
Synapses exhibit different short-term plasticity patterns and this behaviour influences information processing in neuronal networks. We tested how the short-term plasticity of excitatory postsynaptic currents (EPSCs) depends on the postsynaptic cell type, identified by axonal arborizations and molecular markers in the hippocampal CA1 area. Three distinct types of short-term synaptic behaviour (facilitating, depressing and combined facilitating-depressing) were defined by fitting a dynamic neurotransmission model to the data. Approximately 75 % of the oriens-lacunosum-moleculare (O-LM) interneurones received facilitating EPSCs, but in three of 12 O-LM cells EPSCs also showed significant depression. Over 90 % of the O-LM cells were immunopositive for somatostatin and mGluR1alpha and all tested cells were decorated by strongly mGluR7a positive axon terminals. Responses in eight of 12 basket cells were described well with a model involving only depression, but the other cells displayed combined facilitating-depressing EPSCs. No apparent difference was found between the plasticity of EPSCs in cholecystokinin- or parvalbumin-containing basket cells. In oriens-bistratified cells (O-Bi), two of nine cells showed facilitating EPSCs, another two depressing, and the remaining five cells combined facilitating-depressing EPSCs. Seven of 10 cells tested for somatostatin were immunopositive, but mGluR1alpha was detectable only in two of 11 tested cells. Furthermore, most O-Bi cells projected to the CA3 area and the subiculum, as well as outside the hippocampal formation. Postsynaptic responses to action potentials recorded in vivo from a CA1 place cell were modelled, and revealed great differences between and within cell types. Our results demonstrate that the short-term plasticity of EPSCs is cell type dependent, but with significant heterogeneity within all three interneurone populations.
Losonczy
Attila
A
Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary.
Zhang
Limei
L
Shigemoto
Ryuichi
R
Somogyi
Peter
P
Nusser
Zoltan
Z
D000818:Animals; D001369:Axons / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000378:metabolism; D003712:Dendrites / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D006624:Hippocampus / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000737:chemistry / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D009415:Nerve Net / Q000166:cytology / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism; D018408:Patch-Clamp Techniques; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism
D002135:Calcium-Binding Proteins; D009479:Neuropeptides; D018094:Receptors, Metabotropic Glutamate