Ion transport systems in erythrocytes from paramyotonia patients

To test the hypothesis of a general defect in the ion transport systems in the cell membranes of patients with paramyotonia congenita, we measured the ouabain-inhibitable and the furosemide-inhibitable K+ influxes in erythrocytes from two patients. In the temperature range examined (15-40 degrees C), the ouabain-inhibitable flux did not differ significantly from control. Also the furosemide-inhibitable flux was well in the rather large control range. The dependence of these fluxes on the external K+ concentration was normal. Energy depletion of the erythrocytes by preincubation with desoxy-glucose led to reduced K+ influxes that were not significantly different in patients and controls. The results do not support the hypothesis of a general defect in the ion transport systems in paramyotonia; they do, however, not rule out the possibility that the ion transport systems in paramyotonic skeletal muscle are defect.