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.
authors: Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands.
authors: Marlies
authors: M
authors: Oostland
authors: Jim
authors: J
authors: Sellmeijer
authors: Johannes A
authors: JA
authors: van Hooft
mesh_terms: D000818:Animals; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic; D018408:Patch-Clamp Techniques; D010880:Piperidines / Q000494:pharmacology; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology*; D044406:Receptors, Serotonin, 5-HT3 / Q000235:genetics / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: D010880:Piperidines; D044406:Receptors, Serotonin, 5-HT3; D017366:Serotonin Receptor Agonists; D012701:Serotonin; C083009:4-amino-1-(6-chloro-2-pyridyl)piperidine hydrochloride