Autoradiographic localization of [3H]choline uptake in the brain of Drosophila melanogaster.

We describe the localization of sites for choline uptake in the brain of Drosophila melanogaster by the technique of autoradiography of diffusible substances. After systemic injection of [3H]choline, heavy labelling is found in certain regions of the ventral mid-brain, the antennal mechanosensory system including certain commissures, the olfactory lobes and the antennal glomerular tract. This accumulation of label is sensitive to hemicholinium-3 and can be suppressed by incubation at 0 degrees C. It is proposed that acetylcholine is a major neurotransmitter of the antennal mechanosensory and chemosensory systems of Drosophila.