As the opioid crisis continues to harm the nation researchers with University of Utah Health have conducted new studies which aim to uncover the deeper causes of addiction.
Rather than testing on human subjects researchers took an unorthodox yet far safer approach to their study. The main subjects of the opioid testing were zebrafish, which share 70 percent of their genes with humans and have similar biological pathways as well.
The primary goal of this study was to determine greater underlying causes of addiction in humans by studying biological pathways which make humans and animals prone to addiction in the first place as well as withdrawal symptoms. By gaining insight on these causes researchers believe that they would be able to determine new types of therapies and treatment to curb opioid addiction and dependence.
Hydrocodone was used in the study as the fish were able to self-administer the drug in controlled tanks. The drug itself is a prescription painkiller that is widely abused in the United States. Researchers built a control tank which used motion-activated platforms to drop food into the fish tank when fish swam over them. After the controlled tests were completed the same system was used again, only this time releasing a dose of hydrocodone into the tank rather than food.
In order to develop addiction among the zebrafish the tank was continually being flushed of previous doses, thus forcing the fish to work for more. The worst cases of addiction force those affected to go to great lengths to get their dose, which is just what the study intended to do.
As the trials continued and the fish received more doses of the drug, researchers began to note signs of addiction in the fish. To test the dependence the fish built up the drug began being administered in shallow water, which is normally a high-stress environment for fish. Unlike fish not dosed with the painkillers, the seemingly addicted zebrafish had no issue heading to shallow water to receive their next dose.
Randall T. Peterson of U of U Health said “We didn’t know if zebrafish would be a relevant model for opioid addiction, much less self-administer the drug… What is exciting about this work is that we see many of the hallmarks of addiction in the zebrafish. This could be a useful and powerful model.”
