mGluR1/5 subtype‐specific calcium signalling and induction of long‐term potentiation in rat hippocampal oriens/alveus interneurones

Abstract

Hippocampal inhibitory interneurones demonstrate pathway-and synapse-specific rules of transmission and plasticity, which are key determinants of their role in controlling pyramidal cell excitability. Mechanisms underlying long-term changes at interneurone excitatory synapses, despite their importance, remain largely unknown. We use two-photon calcium imaging and whole-cell recordings to determine the Ca 2+ signalling mechanisms linked specifically to group I metabotropic glutamate receptors (mGluR1α and mGluR5) and their role in hebbian long-term potentiation (

Metabotropic Glutamate Receptor Type 5-Dependent Long-Term Potentiation of Excitatory Synapses on Fast-Spiking GABAergic Neurons in Mouse Visual Cortex

“…Regarding expression sites of LTP of excitatory synapses on inhibitory interneurons, the previous studies in the hippocampus reported the presynaptic expression of LTP (Alle et al, 2001;Perez et al, 2001;Topolnik et al, 2006), although another study reported no change in the paired-pulse ratio of EPSPs of stratum radiatum interneurons, implicating the postsynaptic expression (Lamsa et al, 2005). The present study suggests, for the first time in the visual cortex, that LTP of excitatory synapses on FS-GABA neurons in layer II/III of the cortex may be mainly postsynaptic in origin.…”

“…It was reported, however, that LTP at excitatory synapses on basket cells in the dentate gyrus (Alle et al, 2001) and on interneurons in the stratum oriens/alveus or radiatum of the rat hippocampus (Perez et al, 2001;Topolnik et al, 2006) was induced by paired HFS. The present results in the mouse visual cortex seem consistent with the latter three reports.…”

“…Together it seems reasonable to conclude that LTP of excitatory synapses on FS-GABA neurons in layer II/III of the mouse visual cortex is mediated mainly through an activation of mGluR5. In the rat hippocampus, Topolnik et al (2006) reported that the activation of mGluR1/5 and subsequent Ca 2ϩ signaling pathways play a role in LTP of excitatory synapses at interneurons. In the mouse visual cortex, we further identified that mGluR5, not mGluR1, plays a role in the activation of Ca 2ϩ signaling pathways such as PLC, IP 3 and Ca 2ϩ release from internal stores.…”

Control of neuronal excitability by Group I metabotropic glutamate receptors

“…In this case, G-proteinindependent and Src/ERK-dependent activation of TRPC channels contributes a distinct fast component to responses generated by mGlu 1 but not by mGlu 5 (Topolnik et al 2006).…”

Voltage‐dependent anion channel (VDAC‐1) is required for olfactory sensing in Caenorhabditis elegans

“…In the nervous system, substrates of MAPK are involved in protein synthesis, changes in gene expression, dendritic spine stabilization, receptor insertion and others (Sweatt 2004). MAPK signaling in the central nervous system is essential for synaptic plasticity and memory formation, which are associated with long-term potentiation (Topolnik et al 2006). However, already-known targets of MAPK may not be involved in the olfactory sensation because of their functions and slow kinetics of the activation.…”