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Strain differences in pH-sensitive K+ channel-expressing cells in chemosensory and nonchemosensory brain stem nuclei. J Appl Physiol (1985) 2014 Oct 15;117(8):848-56



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Scopus ID

2-s2.0-84908599397   3 Citations


The ventilatory CO2 chemoreflex is inherently low in inbred Brown Norway (BN) rats compared with other strains, including inbred Dahl salt-sensitive (SS) rats. Since the brain stem expression of various pH-sensitive ion channels may be determinants of the CO2 chemoreflex, we tested the hypothesis that there would be fewer pH-sensitive K(+) channel-expressing cells in BN relative to SS rats within brain stem sites associated with respiratory chemoreception, such as the nucleus tractus solitarius (NTS), but not within the pre-Bötzinger complex region, nucleus ambiguus or the hypoglossal motor nucleus. Medullary sections (25 μm) from adult male and female BN and SS rats were stained with primary antibodies targeting TASK-1, Kv1.4, or Kir2.3 K(+) channels, and the total (Nissl-stained) and K(+) channel immunoreactive (-ir) cells counted. For both male and female rats, the numbers of K(+) channel-ir cells within the NTS were reduced in the BN compared with SS rats (P < 0.05), despite equal numbers of total NTS cells. In contrast, we found few differences in the numbers of K(+) channel-ir cells among the strains within the nucleus ambiguus, hypoglossal motor nucleus, or pre-Bötzinger complex regions in both male and female rats. However, there were no predicted functional mutations in each of the K(+) channels studied comparing genomic sequences among these strains. Thus we conclude that the relatively selective reductions in pH-sensitive K(+) channel-expressing cells in the NTS of male and female BN rats may contribute to their severely blunted ventilatory CO2 chemoreflex.

Author List

Martino PF, Olesiak S, Batuuka D, Riley D, Neumueller S, Forster HV, Hodges MR


Hubert V. Forster PhD Professor in the Physiology department at Medical College of Wisconsin
Matthew R. Hodges PhD Associate Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Brain Stem
Carbon Dioxide
Chemoreceptor Cells
Potassium Channels
Rats, Inbred BN
Rats, Inbred Dahl
jenkins-FCD Prod-468 69a93cef3257f26b866d455c1d2b2d0f28382f14