Cationic Acceptor Sites on the Labellar Chemosensory Neurons of Drosophila Melanogaster

We are studying the molecular basis of salt reception in Drosophila melanogaster. The gustatory sensilla of Drosophila contain two different neurons designated L1 and L2 which respond to salts. Previous work has shown that the L1 neuron responds principally to cations and carries at least two acceptor sites that distinguish different cations (Arora, 1985). We have further obtained biochemical and genetic evidence that at least two types of cationic sites are involved. One of these responds selectively to Na+ while the other is relatively non-specific and responds to a variety of cations. The response of L1 to salts can be inactivated by trypsin. Following inactivation, the response to Na+ and K+ recover with a different time course.