Neuroendocrinology and Neuroimmunology
Author: Analía Mercedes Ferreyra | Email: analiaferreyra0@gmail.com
Analía Mercedes Ferreyra 1°, Esteban Javier Beckwith 1°
1° Instituto de Fisiología, Biología Molecular y Neurociencias, UBA-CONICET, Argentina.
There is evidence that sleep has a supportive role in the immune response. The present study focuses on the concept of sickness behavior, which includes a whole series of behavioral changes that arise in response to immune system activation. Previous results demonstrate that changes in sleep and activity are some of the most common behavioral manifestations of infection, seen in vertebrates and invertebrates. However, we still lack a complete understanding of the mechanisms underlying the interactions between both systems. To investigate this, we used the fly Drosophila melanogaster as an experimental model. Its experimental adaptability, coupled with our knowledge of its sleep and innate immunity mechanisms shared with mammals make it an ideal candidate.
Evaluation of behavioral outcomes to infection were done manually via thoracic injections with a precision microinjector. Monitoring of activity patterns was achieved by real-time tracking and analysis through a behavioral profiling platform. Specifically, we injected Staphylococcus aureus and Enterococcus faecalis, Gram positive lethal bacteria that induce the Toll pathways, one of the insect immune arms. We analyzed lifespan and several activity and sleep parameters. We manage to recapitulate the behavioral responses characterized by an increasing activity and a subsequent reduction to sleep. We also tested different concentrations of bacteria, searching for a sublethal dose that induce the behavioral change.