Research article summary (published 3 Aug 2009):

Early development of the thalamic inhibitory feedback loop in the primary somatosensory system of the newborn mice.

Full Abstract

Spontaneous neuronal activity plays an important role during the final development of the brain circuits and the formation of the primary sensory maps. In young rats, spindle bursts have been recorded in the primary somatosensory cortex. They are correlated with spontaneous muscle twitches and occur before active whisking. They bear similarities with the spindles recorded in adult brain that occur during early stages of sleep and rely on a thalamic feedback loop between the glutamatergic nucleus ventroposterior medialis (nVPM) and the GABAergic nucleus reticularis thalami (nRT). However, whether a functional nVPM-nRT loop exists in newborn rodents is unknown. We studied the reciprocal synaptic connections between nVPM and nRT in thalamic acute slices from mice from birth [postnatal day 0 (P0)] until P9. We first demonstrated that nVPM-to-nRT EPSCs could be distinguished from corticothalamic EPSCs by their inhibition by 5-HT attributable to the transient expression of functional presynaptic serotonin 1B receptors. The nVPM-to-nRT EPSCs and nRT-to-nVPM IPSCs were both detected the first day after birth; their amplitude near 2 nS was relatively stable until P5. At P6-P7, there was a rapid and simultaneous increase of both nVPM-to-nRT EPSCs and nRT-to-nVPM IPSCs that reached 8 and 9 nS, respectively. Our results show that the thalamic synapses implicated in spindle activity are functional shortly after birth, suggesting that they could already generate spindles during the first postnatal week. Our results also suggest an inhibitory action of 5-HT on the spindle bursts of the newborn mice.

Author information

Author/s: Evrard, Alexis (A); Ropert, Nicole (N);

Affiliation: INSERM, Unité 603, Centre National de Recherche Scientifique, UMR 8154, and Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, 75006 Paris, France.

Journal and publication information

Publication Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)

Reference: 2009-Aug; vol 29 (issue 31) : pp 9930-40

Dates: Created 2009/08/06; Completed 2009/08/21;

PMID: 19657043, status: MEDLINE (last retrieval date: 8/21/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Aging Analysis of Variance Animals Animals, Newborn Excitatory Postsynaptic Potentials Glutamic Acid - metabolism Inhibitory Postsynaptic Potentials Mice Neural Pathways - growth & development; metabolism Patch-Clamp Techniques

Patch-Clamp Techniques Receptor, Serotonin, 5-HT1B - agonists; metabolism Receptors, AMPA - metabolism Receptors, GABA-A - metabolism Receptors, N-Methyl-D-Aspartate - metabolism Serotonin - metabolism Somatosensory Cortex - growth & development; metabolism Thalamic Nuclei - growth & development; metabolism Thalamus - growth & development; metabolism Time Factors

Associated Chemicals: Receptor, Serotonin, 5-HT1B (0) ; Receptors, AMPA (0) ; Receptors, GABA-A (0) ; Receptors, N-Methyl-D-Aspartate (0) ; Serotonin (50-67-9) ; Glutamic Acid (56-86-0)

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