Basolateral ion transport mechanisms during fluid secretion by Drosophila Malpighian tubules: Na+ recycling,Na+:K+:2Cl– cotransport and Cl– conductance

Mechanisms of ion transport during primary urine formation by the Malpighian tubule of Drosophila melanogaster were analyzed through measurements of fluid secretion rate, transepithelial ion flux, basolateral membrane potential (V(bl)) and intracellular activities of K(+) (a(K)(i)) and Cl(-) (a(Cl)(i)). Calculation of the electrochemical potentials for both ions permitted assessment of the possible contributions of K(+) channels, …