| First Author | Albrieux M | Year | 2004 |
| Journal | J Neurosci | Volume | 24 |
| Issue | 7 | Pages | 1719-25 |
| PubMed ID | 14973256 | Mgi Jnum | J:90115 |
| Mgi Id | MGI:3042537 | Doi | 10.1523/JNEUROSCI.3548-02.2004 |
| Citation | Albrieux M, et al. (2004) Early expression of sodium channel transcripts and sodium current by cajal-retzius cells in the preplate of the embryonic mouse neocortex. J Neurosci 24(7):1719-25 |
| abstractText | In mouse, the first neurons are generated at embryonic day (E) 12 and form the preplate (PP), which contains a mix of future marginal zone cells, including Cajal-Retzius cells, and subplate cells. To detect developmental changes in channel populations in these earliest-generated neurons of the cerebral cortex, we studied the electrophysiological properties of proliferative cells of the ventricular zone and postmitotic neurons of the PP at E12 and E13, using whole-cell patch-clamp recordings. We found an inward sodium current in 55% of PP cells. To determine whether sodium currents occur in a specific cell type, we stained recorded cells with an antibody for calretinin, a calcium-binding protein found specifically in Cajal-Retzius cells. All calretinin-positive cells had sodium currents, although so did some calretinin-negative cells. To correlate the Na current expression to Na channel gene expression with the Cajal-Retzius cell phenotype, we performed single-cell reverse transcription-PCR on patch-clamp recorded cells to detect expression of the Cajal-Retzius cell marker reelin and the Na channel isoforms SCN 1, 2, and 3. These results showed that virtually all Cajal-Retzius cells (97%), as judged by reelin expression, express the SCN transcript identified as the SCN3 isoform. Of these, 41% presented a functional Na current. There is, however, a substantial SCN-positive population in the PP (27% of SCN-positive cells) that does not express reelin. These results raise the possibility that populations of pioneer neurons of the PP, including Cajal-Retzius cells, gain neuronal physiological properties early in development via expression of the Na(v)1.3 (SCN3) Na channel isoform. |
