Calcium Signaling Pathways Involved in Long-Term Potentiation at Excitatory Synapses on Parvalbumin Positive Fast-Spiking GABAergic Neurons in the Mouse Visual Cortex

Objective: recently, we reported the presence of metabotropic glutamate receptor type 5(mglur-5) dependent long-term potentiation (ltp) at excitatory synapses on fast-spikinggabaergic (fs-gaba) cells in the visual cortex. in this study, we report a ca2+ signalingpathway involved in this ltp type.materials and methods: brain slices from gad67-gfp knock-in mice were used. usingwhole-cell patch-clamp recording followed by immunohistochemical staining on parvalbumin-positive (pv+) fs-gaba cells, we studied the ca2+ signaling pathway involved inexcitatory ltp of certain visual cortical interneuron subtypes.results: u-73122- a phospolipas c (plc) inhibitor (10 ىm), inositol triphosphate (ip3) inhibitorssuch as 2-apb (3 ىm) and heparin (10 iu/ml), and cpa- the internally stored ca2+release inhibitor- (5 ىm) blocked the mglur5 signaling pathway to induce ltp at excitatorysynapses on pv+ fast-spiking cells in the visual cortex. however, application of the vehiclesalone had no effect.conclusion: our results indicate that mglur-5 at fs-gaba neurons activate plc andip3 production. this leads to ca2+ release, promotes ltp induction, and its maintenance issupported by internal ca2+ stores. considering the key role of pv+ fs inhibitory neurons inthe visual cortex circuits, we suggest that the metabotropic glutamate receptor-dependentltp of excitatory synapses to fs cells plays a crucial role in the visual cortex plasticity.