Tetraethylammonium and nicotine transport by the Malpighian tubules of insects

We examined transepithelial transport of the prototypical type I organic cation (OC) tetraethylammonium (TEA) and the plant alkaloid nicotine by the isolated Malpighian tubules (MTs) of nine insect species from six orders. Isolated tubules were exposed to radiolabelled forms of either TEA or nicotine in the bathing (basal) fluid. Luminal (apical) secreted fluid was collected and TEA or nicotine concentration was determined. Active net transport …