Abstract
Neuronal membrane channels of Drosophila melanogaster were altered either genetically or pharmacologically in order to investigate the role of specific ionic currents in the acquisition and retention of a conditioned behavior. Conditioning could not be detected for Shaker mutants, in which the fast transient potassium current (IA) is altered; a second potassium channel mutant, eag (ether a go-go) is conditioned like wild type, but the retention period is abnormally short. The napts mutant (no action potential, temperature sensitive), in which nerve excitability is reduced, also expresses normal acquisition and a shortened period of retention. Double mutants of Sh5 and napts as well as Sh5 treated with tetrodotoxin, are essentially normal with respect to acquisition; in both cases these flies remain retention-defective. These experiments therefore reveal a behavioral phenotype of Drosophila mutants in which the primary physiological defect seems to be in the functioning of specific neuronal ionic channels.
