title: Cell type-specific, presynaptic LTP of inhibitory synapses on fast-spiking GABAergic neurons in the mouse visual cortex.
abstract: Properties and plasticity of inhibitory synapses on fast-spiking (FS) GABAergic (FS-GABA) interneurons in layer II/III of the mouse visual cortex were examined in cortical slices by whole-cell recordings of IPSCs or IPSPs evoked by activation of presynaptic FS or non-FS GABAergic interneurons. Unitary IPSCs (uIPSCs) evoked by action potentials of FS-GABA neurons have shorter onset latency, faster rising slope, higher peak amplitude, and faster decay time than those evoked by action potentials of non-FS-GABA neurons. Tetanic activation of presynaptic FS-GABA neurons induced long-term potentiation (LTP) of uIPSCs, whereas that of presynaptic non-FS-GABA neurons did not induce LTP, indicating that long-term plasticity of inhibitory synapses on FS-GABA neurons is pathway specific. For further analysis of inhibitory synaptic plasticity, IPSPs evoked by electrical stimulation of an adjacent site in the cortex were recorded from FS-GABA neurons. Theta burst stimulation induced LTP of IPSPs in 12 of 14 FS-GABA neurons. The paired-pulse stimulation protocol and coefficient of variation analysis indicated that this form of LTP may be presynaptic in origin. Filling postsynaptic cells with a Ca(2+) chelator did not block the induction of LTP, suggesting no involvement of postsynaptic Ca(2+) rise. Also, this form of LTP was dependent neither on metabotropic glutamate receptors nor voltage-gated Ca(2+) channels of the L and T types. Further pharmacological analysis indicated that voltage-gated Ca(2+) channels other than the P/Q type, such as N and R types, were not involved in LTP, suggesting that P/Q-type channels are a candidate for factors inducing LTP of inhibitory synapses between FS-GABA neurons.
authors.affiliation: Brain Science Institute RIKEN, Wako 351-0198 Japan.
authors.forename: Abdolrahman
authors.initials: A
authors.lastname: Sarihi
authors.forename: Javad
authors.initials: J
authors.lastname: Mirnajafi-Zadeh
authors.forename: Bin
authors.initials: B
authors.lastname: Jiang
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sohya
authors.forename: Mir-Shahram
authors.initials: MS
authors.lastname: Safari
authors.forename: Masoumeh Kourosh
authors.initials: MK
authors.lastname: Arami
authors.forename: Yuchio
authors.initials: Y
authors.lastname: Yanagawa
authors.forename: Tadaharu
authors.initials: T
authors.lastname: Tsumoto
mesh_terms: D000200:Action Potentials / Q000235:genetics / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D055592:Biophysical Phenomena / Q000187:drug effects / Q000235:genetics; D001703:Biophysics; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D059330:GABAergic Neurons / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D015767:Mefloquine / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D013997:Time Factors; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000235:genetics; D014793:Visual Cortex / Q000166:cytology*
chemical_list: D002121:Calcium Channel Blockers; D018691:Excitatory Amino Acid Antagonists; D058787:GABA-A Receptor Antagonists; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; D049452:Green Fluorescent Proteins; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D002118:Calcium; D015767:Mefloquine; D001640:Bicuculline