Serotonin 3A receptor subtype as an early and protracted marker of cortical interneuron subpopulations.
To identify neocortical neurons expressing the type 3 serotonergic receptor, here we used transgenic mice expressing the enhanced green fluorescent protein (GFP) under the control of the 5-HT(3A) promoter (5-HT(3A):GFP mice). By means of whole-cell patch-clamp recordings, biocytin labeling, and single-cell reversed-transcriptase polymerase chain reaction on acute brain slices of 5-HT(3A):GFP mice, we identified 2 populations of 5-HT(3A)-expressing interneurons within the somatosensory cortex. The first population was characterized by the frequent expression of the vasoactive intestinal peptide and a typical bipolar/bitufted morphology, whereas the second population expressed predominantly the neuropeptide Y and exhibited more complex dendritic arborizations. Most interneurons of this second group appeared very similar to neurogliaform cells according to their electrophysiological, molecular, and morphological properties. The combination of 5-bromo-2-deoxyuridine injections with 5-HT(3A) mRNA detection showed that cortical 5-HT(3A) interneurons are generated around embryonic day 14.5. Although at this stage the 5-HT(3A) receptor subunit is expressed in both the caudal ganglionic eminence and the entopeduncular area, homochronic in utero grafts experiments revealed that cortical 5-HT(3A) interneurons are mainly generated in the caudal ganglionic eminence. This protracted expression of the 5-HT(3A) subunit allowed us to study specific cortical interneuron populations from their birth to their final functional phenotype.
Vucurovic
Ksenija
K
CNRS-UMR 7637, Laboratoire de Neurobiologie, ESPCI ParisTech, 75005 Paris, France.
Gallopin
Thierry
T
Ferezou
Isabelle
I
Rancillac
Armelle
A
Chameau
Pascal
P
van Hooft
Johannes A
JA
Geoffroy
Hélène
H
Monyer
Hannah
H
Rossier
Jean
J
Vitalis
Tania
T
D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism; D051837:COUP Transcription Factor II / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D004622:Embryo, Mammalian; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D007395:Interneurons / Q000145:classification* / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3 / Q000235:genetics / Q000378:metabolism*; D013003:Somatosensory Cortex / Q000166:cytology*; D018709:Statistics, Nonparametric; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D051837:COUP Transcription Factor II; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; C497587:Nr2f2 protein, mouse; D010320:Parvalbumins; D021122:Protein Subunits; D044406:Receptors, Serotonin, 5-HT3; D049452:Green Fluorescent Proteins; D014660:Vasoactive Intestinal Peptide; D001973:Bromodeoxyuridine