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.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to scicrunch, however this is not currently a free service.