| First Author | Wang S | Year | 2013 |
| Journal | J Neurosci | Volume | 33 |
| Issue | 18 | Pages | 7756-61 |
| PubMed ID | 23637167 | Mgi Jnum | J:248635 |
| Mgi Id | MGI:6093808 | Doi | 10.1523/JNEUROSCI.5550-12.2013 |
| Citation | Wang S, et al. (2013) Phox2b-expressing retrotrapezoid neurons are intrinsically responsive to H+ and CO2. J Neurosci 33(18):7756-61 |
| abstractText | Central respiratory chemoreceptors sense changes in CO2/H(+) and initiate the adjustments to ventilation required to preserve brain and tissue pH. The cellular nature of the sensors (neurons and/or glia) and their CNS location are not conclusively established but the glutamatergic, Phox2b-expressing neurons located in the retrotrapezoid nucleus (RTN) are strong candidates. However, a direct demonstration that RTN neurons are intrinsically sensitive to CO2/H(+), required for designation as a chemosensor, has been lacking. To address this, we tested the pH sensitivity of RTN neurons that were acutely dissociated from two lines of Phox2b-GFP BAC transgenic mice. All GFP-labeled cells assayed by reverse transcriptase-PCR (n = 40) were Phox2b+, VGlut2+, TH-, and ChAT-, the neurochemical phenotype previously defined for chemosensitive RTN neurons in vivo. We found that most dissociated RTN neurons from both lines of mice were CO2/H(+)-sensitive ( approximately 79%), with discharge increasing during acidification and decreasing during alkalization. The pH-sensitive cells could be grouped into two populations characterized by similar pH sensitivity but different basal firing rates, as previously observed in recordings from GFP-labeled RTN neurons in slice preparations. In conclusion, these data indicate that RTN neurons are inherently pH-sensitive, as expected for a respiratory chemoreceptor. |
