Effects of Amiloride on the Transport of Sodium and Other Ions in the Alga Hydrodictyon reticulatum

Abstract. The diuretic amiloride, an almost specific inhibitor of sodium trans port in animal cells and tissues, appears to produce a number of effects in the alga Hydrodictyon reticulatum. At 1 mmol 1 concentration it markedly reduces the influx of sodium ions (but not their active outflux), the influxes of potassium, chloride as well as of bicarbonate ions, and causes a profound decrease in the plasmalemma membrane potential. This plurality of inhibitory effects suggests that individual transport processes in the alga are mutually coupled