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NHE1, NHE3, and NHE5 mRNA expression in brainstem and cortex of Sprague‐Dawley rat
Author(s) -
Perkins Matthew Huntoon,
Pritz Maria Magdalena,
Cordovez Juan M,
Solomon Irene C
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.621.3
Subject(s) - brainstem , gene isoform , sodium–hydrogen antiporter , medulla , intracellular ph , dorsal raphe nucleus , chemistry , messenger rna , cortex (anatomy) , medicine , endocrinology , medulla oblongata , in situ hybridization , biology , microbiology and biotechnology , central nervous system , neuroscience , intracellular , sodium , biochemistry , gene , serotonin , serotonergic , receptor , organic chemistry
In brainstem CO 2 chemosensitive neurons, an increase in CO 2 (hypercapnia) leads to a maintained reduction in intracellular pH (pH i ) while in non‐chemosensitive neurons, pH i recovery is observed. Although the precise mechanisms for this difference in pH i regulation remain to be determined, it has been suggested that different isoforms of the Na + /H + ‐exchanger (NHE) may be responsible. To begin to explore this possibility, real‐time RT‐PCR was used to examine mRNA expression for three NHE isoforms ‐ NHE1 (Slc9a1), NHE3 (Slc9a3), and NHE5 (Slc9a5) ‐ in brainstem and cortex (non‐chemosensitive control) of 21 day‐old SD rat. Preliminary data indicate that each of the NHE isoforms is present in both brainstem and cortex. To further investigate the distribution within the medulla, mRNA expression levels for the NHE3 and NHE5 in dorsal (dM) versus ventral (vM) medulla were compared. These analyses revealed that NHE5 mRNA levels are ~4‐fold higher in the vM than in the dM (when normalized to Actb), but NHE3 mRNA levels are similar between the two regions. Additional studies are needed to further evaluate the relative abundance of different NHE mRNAs in chemosensitive areas such as the NTS/DMV, VLM, the caudal medullary raphe, and the LC. To date, however, our data suggest that differential expression of NHE isoforms may participate in pH i regulation in chemosensitive and/or non‐chemosensitive neurons. Supported by NS045321.