Rat cardiac hypertrophy. Altered sodium-calcium exchange activity in sarcolemmal vesicles.
The sodium-calcium exchange activity has been studied in sarcolemmal vesicles isolated from rat ventricles hypertrophied by pressure overload. 4 weeks after aortic stenosis the degree of hypertrophy varied from 30 to 70%. The Na+-dependent 45Ca2+ influx and efflux were up to 50% decreased and the sensitivity to Ca2+ was 13-fold lower in vesicles from hypertrophied heart as compared to those from normal heart. However, the Na+,K+-ATPase activity, the orientation of the vesicles and the passive Ca2+ permeability were found to be similar in the two heart groups. These results indicate that the sarcolemmal Na+/Ca2+ exchange activity could be qualitatively and/or quantitatively changed in hypertrophied rat heart.
Hanf
R
R
INSERM U127, Universitè Paris 7, Hôpital Lariboisière, Paris, France.
Drubaix
I
I
Marotte
F
F
Lelievre
L G
LG
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006332:Cardiomegaly / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D008861:Microsomes / Q000378:metabolism / Q000648:ultrastructure; D008929:Mitochondria, Heart / Q000378:metabolism / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012508:Sarcolemma / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D002118:Calcium