Electrochemical gradients for Na+, K+,Cl– and H+ across the apical membrane in Malpighian (renal) tubule cells of Rhodnius prolixus

Measurements of intracellular and luminal ion activities as well as membrane potential were used to calculate electrochemical gradients for Cl-, Na+, K+ and H+ across the apical membrane during fluid secretion by Malpighian tubules of Rhodnius prolixus. The results show that the contribution of Na+/H+ and/or K+/H+ exchangers to fluid secretion is feasible both in unstimulated and serotonin-stimulated tubules. Similarly, the electrochemical …