Prp57 Transgenic Mice Express Multiple pH Sensitive Ion Channels in CO2/H+ Sensitive GFP+ Locus Coeruleus Neurons

• Published in: The FASEB journal 2008-04, Vol.22 (S2), p.174-174
• Main Authors: Johnson, Sheree M, Rogulin, Vitaliy, Richerson, George B
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.22.2_supplement.174

The locus coeruleus (LC) is a putative central respiratory chemoreceptive site containing neurons that are sensitive to perturbations in CO2/H+. In previous studies of the Prp57 transgenic mouse that expresses green fluorescent protein (GFP) in the LC, we demonstrated that cultured GFP‐LC neurons exposed to CO2/H+ increased or decreased their firing rate (FR) during hypercapnic acidosis (HA) and hypocapnic alkalosis, respectively. It remains unclear what pH sensitive ion channels are present in LC neurons that are responsible for the CO2/H+ induced changes in FR. We hypothesized that multiple pH sensitive channels may be present in GFP‐LC neurons. We used immunofluorescence to identify GFP‐LC neurons that co‐expressed TASK‐1, Kir4.1 and Kir5.1 pH sensors in Prp57 mice and observed tissues with a fluorescent microscope. Preliminary data suggest that GFP‐LC neurons co‐expressed TASK‐1 and Kir5.1, but not Kir4.1, indicating that a combination of pH sensors may be responsible for changes in FR. We conclude that catecholaminergic GFP‐LC neurons express a heterogeneous collection of pH sensitive ion channels that are likely involved in mediating responses to physiological CO2/H+ fluctuations observed in vitro as well as in the intact animal. Supported by NS047422 to SMJ, NICHD to GBR and in part by NS039407.