Octopamine Signaling Via Oamb is Essential for A Well-Orchestrated Climbing Performance of Adult Drosophila Melanogaster
Abstract The biogenic amine octopamine (OA) orchestrates many behavioural processes in insects. OA mediates its function by binding to OA receptors belonging to the G protein-coupled receptors superfamily. Despite the potential relevance of OA for controlling locomotion, our knowledge about the role of each octopaminergic receptor still limited. In this study, RNA interference (RNAi) was used to knockdown each OA receptor type in almost all Drosophila melanogaster tissues using a tubP-GAL4 driver to investigate the loss of which receptor affects the climbing ability of adult flies. The results demonstrated that oamb-deficient flies had impaired climbing ability more than those deficient in other receptors receptive for OA. Targeted RNAi-mediated kockdown of oamb in the nervous system or muscular system decreased the climbing ability, indicating that within Drosophila legs, OA through oamb orchestrated the nervous system control and muscular tissue responses. Oamb-deficient adult males showed morphometric changes in the length and width of leg parts. Transmission electron microscopy revealed that the leg muscles oamb-deficient flies have severe ultrastructural changes compared to those of control flies. The severe impairment in the climbing performance of oamb-deficient flies correlates well with the completely distorted leg muscle ultrastructure in these flies. Taken together, we could conclude that OA via oamb plays an important role in the locomotor activity of Drosophila.