title: Potassium measurements in the extracellular spaces of normal and failing cat myocardium.
abstract: After periods of quiescence, papillary muscles and trabeculae from normal and hypertrophied-failing cat hearts were subjected to ionic stress induced by stimulation (drive) at different frequencies. Patterns of change in extracellular potassium concentration were measured using ion-selective microelectrodes and were shown to be significantly different in certain key parameters. In both types of tissue, extracellular potassium activity initially increased from the level in the bathing medium, reached a peak, and then returned toward the original levels. However, the time for this to occur was significantly longer in the hypertrophied-failing muscles than in the normal controls. Also, after more than 5 min of drive, the potassium activity in the extracellular spaces was significantly higher in the hypertrophied-failing tissue than in the normal tissue. The results of these experiments indicate that there may be quantitative differences between normal and hypertrophied-failing cardiac muscles with regard to the regulation of ionic balance.
mesh_terms: D000818:Animals; D006332:Cardiomegaly / Q000378:metabolism; D002415:Cats; D004558:Electric Stimulation; D005110:Extracellular Space / Q000032:analysis*; D006324:Heart Arrest, Induced; D066298:In Vitro Techniques; D009206:Myocardium / Q000032:analysis*; D009994:Osmolar Concentration; D011188:Potassium / Q000032:analysis*
chemical_list: D011188:Potassium