RT Journal Article
SR Electronic
T1 POSSIBLE INVOLVEMENT OF CARDIAC Na+ , K+-ADENOSINE TRIPHOSPHATASE IN THE MECHANISM OF ACTION OF CARDIAC GLYCOSIDES
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 31
OP 41
VO 168
IS 1
A1 ARNOLD SCHWARTZ
A1 JULIUS C. ALLEN
A1 SHOICHI HARIGAYA
YR 1969
UL http://jpet.aspetjournals.org/content/168/1/31.abstract
AB The effects of ouabain and digoxin on a cardiac Na+, K+-adenosine triphosphatase (Na+, K+-ATPase) from dog and beef were monitored with a continuous recording spectrophotometer. A time and temperature dependence of glycoside-induced inhibition was found. Increasing the time of enzyme exposure to the drug and increasing the temperature of incubation resulted in a significant enhancement of cardiac glycoside action. Half-maximal inhibitory concentration at 45°C and after 30-minute exposure was 0.025 µM for beef heart. The binding of H3-ouabain to the Na+ , K+-ATPase appeared to be related to the inhibitory effect of ouabain on Na+, K+-ATPase. An active cardiac relaxing system did not bind H3-digoxin or H3-ouabain, nor was Ca++ binding or uptake affected by a wide range of glycoside concentrations. Cardiac mitochondria were not affected by ouabain or digoxin. It is concluded that the Na+, K+-ATPase may be involved in the action of cardiac glycosides. © 1969, by The Williams & Wilkins Company