@article{130026, keywords = {Animals, Mice, Female, Male, Mice, Transgenic, In Vitro Techniques, Membrane Potentials, Patch-Clamp Techniques, Cerebellum, Serotonin, Purkinje Cells, Receptors, Serotonin, 5-HT3, Piperidines, Serotonin Receptor Agonists}, author = {Marlies Oostland and Jim Sellmeijer and van Johannes Hooft}, title = {Transient expression of functional serotonin 5-HT3 receptors by glutamatergic granule cells in the early postnatal mouse cerebellum}, abstract = { The serotonin 5-HT(3) receptor is the only ligand-gated ion channel activated by serotonin and is expressed by GABAergic interneurons in many brain regions, including the cortex, amygdala and hippocampus. Furthermore, 5-HT(3) receptors are expressed by glutamatergic Cajal-Retzius cells in the cerebral cortex. We used 5-HT(3A)/enhanced green fluorescent protein (EGFP) transgenic mice to show that 5-HT(3) receptors are also ubiquitously expressed by glutamatergic granule cells in the cerebellum during the first three postnatal weeks. Using whole-cell patch clamp recordings, we show that local application of either serotonin or the selective 5-HT(3) receptor agonist SR57227A to granule cells results in a small inward current, demonstrating a post- and/or extrasynaptic localisation of the 5-HT(3) receptors. Functional 5-HT(3) receptors were also observed presynaptically at the parallel fibre-Purkinje cell synapse. Pharmacological block using the selective 5-HT(3) receptor antagonist tropisetron induced a reduction in the frequency of miniature synaptic events recorded from Purkinje cells. Paired-pulse stimulation of parallel fibres on whole-cell voltage clamped Purkinje cells from 1-week-old mice did not yet show synaptic plasticity. In the presence of tropisetron, the parallel fibre-Purkinje cell synapse showed paired-pulse depression. Taken together, these results show that functional 5-HT(3) receptors are present during early postnatal development in the cerebellum, where they modulate synaptic plasticity. }, year = {2011}, journal = {J Physiol}, volume = {589}, pages = {4837-46}, month = {10/2011}, issn = {1469-7793}, doi = {10.1113/jphysiol.2011.217307}, language = {eng}, }