PT  - JOURNAL ARTICLE
AU  - Alban Laurent
AU  - Jean-Marc Goaillard
AU  - Olivier Cases
AU  - Cécile Lebrand
AU  - Patricia Gaspar
AU  - Nicole Ropert
TI  - Activity-Dependent Presynaptic Effect of Serotonin 1B Receptors on the Somatosensory Thalamocortical Transmission in Neonatal Mice
AID  - 10.1523/JNEUROSCI.22-03-00886.2002
DP  - 2002 Feb 01
TA  - The Journal of Neuroscience
PG  - 886--900
VI  - 22
IP  - 3
4099  - http://www.jneurosci.org/content/22/3/886.short
4100  - http://www.jneurosci.org/content/22/3/886.full
SO  - J. Neurosci.2002 Feb 01; 22
AB  - 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.