Drosophila melanogaster as a model to study the effects of drugs of abuse on brain morphology and on specific neuronal populations

Alcohol and tobacco are consumed by millions of people worldwide, many of which become addicted to these drugs and many of whom die from complications associated with tobacco or alcohol abuse. Drosophila melanogaster is a model organism that has been successfully established in the last 30 years for the study of the genetic and molecular mechanisms of drugs of abuse, including alcohol, nicotine, cocaine and amphetamines. Most studies to date have focused on acute effects of the drugs. However, some studies have also looked at developmental effects of ethanol and nicotine. These studies have shown that known effects of alcohol and nicotine, the addictive compound in tobacco, are recapitulated in the Drosophila model. For example, flies exposed to these drugs have decreased survival, increased development time, and decreased weight. Moreover, these studies have also shown that developmental exposure to these drugs changes the acute response to these drugs in the adult organisms. Both exposure to ethanol or nicotine during development decrease the sensitivity to ethanol sedation in adult flies. In addition, developmental drug exposure resulted in morphological changes in the central nervous system, including changes in brain size and in specific neuronal populations. In particular, these studies have shown that insulin and dopamine neurons are altered. More work is needed to continue characterizing the neurological effects of ethanol and nicotine after developmental exposure. Drosophila melanogaster, with its fast generation time and documented similarities in some of the effects of these drugs in mammalian systems, is a complementary model to continue learning about how these drugs change the nervous system and how those changes impact behaviors later in life. In addition, the state-of-the-art molecular tools available to Drosophila researchers, make it a great model to elucidate genetic and molecular mechanisms that may uncover new targets for treatments of the effects of drugs of abuse during development.