Intracellular Na+ activity of "diseased" human atrial muscles and its modifications by dihydro-ouabain.
In quiescent human atrial muscles obtained from patients with various cardiac diseases, the intracellular Na+ activity (aNai) and the resting membrane potential (Vm) were recorded simultaneously, using double-barreled Na(+)-selective microelectrodes. The Vm averaged -44.1 +/- 5.0 mV and the aNai, 6.9 +/- 1.7 mM under normal Tyrode's solution containing 5.4 mM [K]oi,The aiNa value was within the range of aNai reported in various cardiac tissues from intact animals. Dihydro-ouabain (10(-5) M) significantly increased the aNai and depolarized the Vm. The results suggest that even in these depolarized atrial muscles the aNai remains within physiologic levels and that the Na-K pump may not be impaired. This is the first report to measure the aNai in human atrial muscles.
Kajita
J
J
Department of Physiology, Oita Medical University, Japan.
Imanishi
S
S
Sako
H
H
Arita
M
M
Hadama
T
T
D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006325:Heart Atria / Q000378:metabolism*; D006331:Heart Diseases / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000031:analogs & derivatives* / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*
C000977:dihydroouabain; D010042:Ouabain; D012964:Sodium