3H]ouabain binding in skeletal muscle from horses with hyperkalemic periodic paralysis
Pickar, J.G.; Spier, S.J.; Harrold, D.; Carlsen, R.C.
American Journal of Veterinary Research 54(5): 783-787
1993
ISSN/ISBN: 0002-9645 PMID: 8391230 Document Number: 410990
Ouabain, a cardiac glycoside, binds to the Na(+)-K(+)-adenosine triphosphatase (Na+ pump) and prevents active transport of Na+ and K+ across cell membranes. We used ouabain-binding sites (222.3 +/- 21.0 pmol/g vs 225.3 +/- 24.2 pmol/g, respectively). The affinity of these binding sites for ouabain was not different, between adults or foals, in clinically normal or affected horses. Our results indicate that membrane events underlying the periodic episodes of paralysis in horses with HYPP are not attributable to quantitative changes in Na+ pump number or affinity. Our data cannot exclude the possibility that the specific activity of the Na+ pump is altered in muscle from HYPP-affected horses.