title: Activity-dependent presynaptic effect of serotonin 1B receptors on the somatosensory thalamocortical transmission in neonatal mice.
abstract: The disruptive effect of excessive serotonin (5-HT) levels on the development of cortical sensory maps is mediated by 5-HT1B receptors, as shown in barrelless monoamine oxidase A knock-out mice, in which the additional inactivation of 5-HT1B receptors restores the barrels. However, it is unclear whether 5-HT1B receptors mediate their effect on barrel formation by a trophic action or an activity-dependent effect. To test for a possible effect of 5-HT1B receptors on activity, we studied the influence of 5-HT on the thalamocortical (TC) synaptic transmission in layer IV cortical neurons. In TC slices of postnatal day 5 (P5)-P9 neonate mice, we show that 5-HT reduces monosynaptic TC EPSCs evoked by low-frequency internal capsule stimulation and relieves the short-term depression of the EPSC evoked by high-frequency stimulation. We provide evidence that 5-HT decreases the presynaptic release of glutamate: 5-HT reduces similarly the AMPA-kainate and NMDA components and the paired pulse depression of TC EPSCs. We show also that 5-HT1B receptors mediate exclusively the effect of 5-HT: first, the effect of 5-HT on the TC EPSC is correlated with the transient expression of 5-HT1B receptor mRNAs in the ventrobasal thalamic nucleus during postnatal development; second, it is mimicked by a 5-HT1B agonist; third, 5-HT has no effect in 5-HT1B receptor knock-out mice. Our results show that in the developing barrel field of the neonatal mice, 5-HT1B receptors mediate an activity-dependent regulation of the TC EPSC that could favor the propagation of high-frequency TC activity.
authors.affiliation: Laboratoire de Neurophysiologie et Nouvelles Microscopies, Institut National de la Santé et de la Recherche Médicale (INSERM) EPI-0002, Ecole Supérieure de Physique et de Chimie Industrielle, 75231 Paris cedex 5, France,
authors.forename: Alban
authors.initials: A
authors.lastname: Laurent
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Goaillard
authors.forename: Olivier
authors.initials: O
authors.lastname: Cases
authors.forename: Cecile
authors.initials: C
authors.lastname: Lebrand
authors.forename: Patricia
authors.initials: P
authors.lastname: Gaspar
authors.forename: Nicole
authors.initials: N
authors.lastname: Ropert
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009433:Neural Inhibition / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013788:Thalamus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D020651:Ventral Thalamic Nuclei / Q000254:growth & development / Q000378:metabolism
chemical_list: D011725:Pyridines; D011758:Pyrroles; D012333:RNA, Messenger; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C065046:3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrolo(3,2-b)pyrid-5-one; D012701:Serotonin