Neuroscientists researching addiction have found that dynorphin, an opioid hormone produced in the brain, may help facilitate the early stages of the learning process by activating specific neural receptors. These findings may seem small at first, but they hold promising implications for the development of future advancements in the treatment of alcohol use disorder (AUD) as these receptors partially influence the brain’s response to alcohol and have many other clinical applications.
Cody Siciliano and investigators of the Siciliano Lab at Vanderbilt University have been researching the role of neurotransmitters in the development of AUD. This disorder, also commonly known as alcoholism or alcohol dependency, affects approximately 29% of adults who drink alcohol in their lifetime. While most people drink to feel that associated buzz, consistently drinking too much can develop into a dependency driven by the need to get rid of the unpleasant.
Zahra Farabakhsh, a graduate student researcher in the Siciliano Lab, described their current theory to explain AUD: “When you start drinking, you’re drinking for this reward; you’re drinking to increase your mood. And after alcohol leaves your system, you have a little dip in mood and then you go back to your homeostatic point. But as you continue to drink, your reward gets smaller and smaller and the dip after drinking gets deeper.”
To understand these reactions, the Siciliano Lab measured the physical and neural activity of mice which had regularly consumed alcohol over 26 days. These mice were housed in Skinner boxes – controlled environments that animals must learn to operate to receive food – and were injected with either saline solution or NorBNI, a chemical used to help patients with AUD that blocks the receptors of dynorphin, an opioid hormone in the body. The mice also underwent positive or negative reinforcement by using a button in the Skinner box to either receive food or stop electrical shocks.
The experimenters found that blocking the receptors with NorBNI increased early learning in the mice regardless of the type of reinforcement, the opposite effect to what was predicted. They then injected the mice with optic fibers and kLight, a molecule that fluoresces when near dynorphin, to record their brain activity. The kLight revealed an increase in neural signaling when the mice consumed substances that they were dependent on, providing further support for the theory that dynorphin and its receptors play a role in learning and the brain’s reward system.
While these results have yet to be officially published, they reveal a path towards further understanding the interactions between dopamine, dynorphin, and their receptors, as well as the role that they play in alcohol use disorder and learning in general. By understanding the neurological basis of dynorphin signaling, researchers may discover a way to manipulate learning in this and other related pathways. Not only may this potentially lead to the development of medications to treat alcohol abuse, but it may also open an entirely new area of neurobiology to explore and learn from. This new opening presents endless possibilities for advancements in the treatments and care options used to help improve patients’ lives in the future.
Comments
Post a Comment