Characterization of tetraethylammonium uptake across the basolateral membrane of the Drosophila Malpighian (renal) tubule.

Basolateral transport of the prototypical type I organic cation tetraethylammonium (TEA) by the Malpighian tubules of Drosophila melanogaster was studied using measurements of basolateral membrane potential (V(bl)) and uptake of [(14)C]-labeled TEA. TEA uptake was metabolically dependent and saturable (maximal rate of mediated TEA uptake by all potential transport processes, reflecting the total transport capacity of the membrane, 0.87 pmol.