title: Intracellular Na+ activity of "diseased" human atrial muscles and its modifications by dihydro-ouabain.
abstract: 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.
authors.affiliation: Department of Physiology, Oita Medical University, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kajita
authors.forename: S
authors.initials: S
authors.lastname: Imanishi
authors.forename: H
authors.initials: H
authors.lastname: Sako
authors.forename: M
authors.initials: M
authors.lastname: Arita
authors.forename: T
authors.initials: T
authors.lastname: Hadama
mesh_terms: 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*
chemical_list: C000977:dihydroouabain; D010042:Ouabain; D012964:Sodium