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Numbers of pH‐sensitive K + channel‐immunoreactive neurons are reduced in CO 2 ‐insensitive Brown Norway rats in select brainstem nuclei associated with central respiratory chemoreception (1092.8)
Author(s) -
Martino P,
Olesiak S,
Riley D,
Neumueller S,
Forster H,
Hodges M
Publication year - 2014
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.28.1_supplement.1092.8
Subject(s) - hypoglossal nucleus , nucleus , brainstem , solitary tract , chemistry , medicine , anatomy , endocrinology , chemoreceptor , electrophysiology , respiratory system , biology , neuroscience , receptor
Brown Norway (BN) rats display an extremely low hypercapnic ventilatory response (HCVR) compared to other strains such as the Dahl S (SS) rat. Multiple pH‐sensitive potassium (K+) channels are expressed within multiple brainstem chemosensory nuclei and may contribute to CO2‐H+ detection/signaling in chemosensitive neurons. Herein we tested the hypothesis that there are selective reductions in the numbers of neurons expressing pH‐sensitive Kv1.4, Kir 2.3, and TASK‐1 K+ channels in the chemosensory nucleus of the solitary tract (NTS) but not in the pre‐Botzinger Complex (pre‐BötC), nucleus ambiguus (NA) or hypoglossal nucleus (XII) of BN but not SS rats. Medullary sections (25 µm) from male and female BN (n=14) and SS (n=15) rats were stained with cresyl violet or primary antibodies targeting KV1.4, Kir2.3, or TASK‐1 and the numbers of K+ channel‐immunoreactive (‐ir) neurons were quantified. There was little difference among female and male rats within each strain in all nuclei studied. However, within the NTS there were significantly fewer Kir2.3, (47.46% ± 1.83%; TASK‐1 57.46% ± 2.17%; and Kv1.4 64.11% ± 1.6% observed in BN rats as compared to SS rats. In contrast, the numbers of K+ channel‐ir neurons did not significantly (P< 0.05) differ within the NA and the hypoglossal nucleus, with some significant (P < 0.05) differences observed in the Medullary Raphe and the pre‐Botzinger complex. Fewer pH sensitive K+ channel‐immunoreactive neurons is evidence that at least partly explains the lower hypercapnic response in BN rats compared to that in SS rats. Grant Funding Source : Supported by the Department of Veterans Affairs and NIH HL25739