Nicotine has a therapeutic window of effectiveness in a Drosophila melanogaster model of Parkinson’s disease

Abstract

Strong epidemiological evidence and studies in models of Parkinson’s disease (PD) suggest that nicotine may be therapeutically beneficial in PD patients. However, a number of clinical trials utilizing nicotine in PD patients have had mixed results, indicating that either nicotine is not beneficial in PD patients, or an important aspect of nicotine therapy was absent. Here we show that continuous early nicotine administration improves both climbing and flight deficiencies present in homozygous park25 mutant PD model Drosophila melanogaster. Using a new climbing assay, we identify several climbing deficiencies in this PD model that are improved or rescued by nicotine treatment. Amongst these benefits, it appears that nicotine improves the ability of the park25 flies to descend the climbing vial by being able to climb down more. Importantly, we show that in order for nicotine benefits on climbing and flight to happen, nicotine administration must occur in a discrete time frame following adult fly eclosure: within one day for climbing or five days for flight. This therapeutic window of nicotine administration may help to explain its lack of efficacy in human clinical trials, suggesting a need to test earlier nicotine therapy in PD patients.