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Differences between three inbred rat strains in number of K+ channel-immunoreactive neurons in the medullary raphé nucleus. J Appl Physiol (1985) 2010 Apr;108(4):1003-10 PMID: 19926827 PMCID: PMC2853200

Pubmed ID

19926827

DOI

10.1152/japplphysiol.00625.2009

Abstract

Ventilatory sensitivity to hypercapnia is greater in Dahl salt-sensitive (SS) rats than in Fawn Hooded hypertensive (FHH) and Brown Norway (BN) inbred rats. Since pH-sensitive potassium ion (K(+)) channels are postulated to contribute to the sensing and signaling of changes in CO(2)-H(+) in chemosensitive neurons, we tested the hypothesis that there are more pH-sensitive K(+) channel-immunoreactive (ir) neurons within the medullary raphé nuclei of the highly chemosensitive SS rats than in the other two strains. Medullary tissues from male and female BN, FHH, and SS rats were stained with cresyl violet or with antibodies targeting TASK-1, K(v)1.4, and Kir2.3 channels. K(+) channel-ir neurons were quantified and compared with the total neurons in the region. The total number of neurons in the medullary raphé 1) was greater in male FHH than the other male rats, 2) did not differ among the female rats, and 3) did not differ between sexes. The average number of K(+) channel-ir neurons per section was 30-60 neurons higher in the male SS than in the other rat strains. In contrast, for the females, the number of K(+) channel-ir neurons was greatest in the BN. We also found significant differences in the number of K(+) channel-ir neurons between sexes in SS (males > females) and BN (females > males) rats, but not the FHH strain. Our findings support the hypothesis for males but not for females, suggesting that both genetic background and sex are determinants of K(+) channel immunoreactivity of medullary raphé neurons, and that the expression of pH-sensitive K(+) channels in the medullary raphé does not correlate with the ventilatory sensitivity to hypercapnia.

Author List

Riley D, Dwinell M, Qian B, Krause KL, Bonis JM, Neumueller S, Marshall BD, Hodges MR, Forster HV

Authors

Melinda R. Dwinell PhD Center Associate Director, Associate 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




Scopus

2-s2.0-77950571666   5 Citations

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

Animals
Cell Count
Female
Hypercapnia
Male
Neurons
Phenotype
Potassium Channels
Raphe Nuclei
Rats
Rats, Inbred Strains
Species Specificity
jenkins-FCD Prod-321 98992d628744e349846c2f62ac68f241d7e1ea70