Optogenetics, pond scum and alcohol addiction: where is the connection?
News Editor: Maria Kostyanaya
Optogenetics, a new technology, allows researchers to control the activity of specific populations of brain cells, or neurons, using light. In it’s application it can help investigators gain a better understanding of the neurochemical basis of addiction.
Interestingly enough, we have pond scum to thank for the new technique! The method was devised to understand how the tiny green algae, that give pond scum its distinctive color, detect and use light to grow.
Most importantly for both theoretical and practical areas allied to neuroscience, the technology allowed Evgeny A. Budygin, Ph.D., an assistant professor of neurobiology and anatomy at Wake Forest Baptist Medical Center, to address critical questions regarding the role of dopamine in alcohol drinking-related behaviors. The latest study from Budygin and his team has been published online in the journal Frontiers in Behavioral Neuroscience.
“With this technique, we’ve basically taken control of specific populations of dopamine cells, using light to make them respond — almost like flipping a light switch,” claims Budygin.
“These data provide us with concrete direction about what kind of patterns of dopamine cell activation might be most effective to target alcohol drinking.”
According to Jeffrey L. Weiner, Ph.D., co-author and professor of physiology and pharmacology at Wake Forest Baptist, one of the biggest challenges in neuroscience has been to control the activity of brain cells in the same way that the brain essentially controls them. With the developments of optogenetics, neuroscientists can turn specific neurons on or off at will, proving that those neurons govern specific behaviors.
“We have known for many years what areas of the brain are involved in the development of addiction and which neurotransmitters are essential for this process,” Weiner says. She adds: “We need to know the causal relationship between neurochemical changes in the brain and addictive behaviors, and optogenetics is making that possible now.”
Using a rodent model, the researchers used cutting-edge molecular techniques to express the light-responsive channel rhodopsin protein in a specific population of dopamine cells in the brain-reward system. They further implanted tiny optical fibers into this brain region and were able to control the activity of these dopamine cells by flashing a blue laser on them.
“You can place an electrode in the brain and apply an electrical current to mimic the way brain cells get excited, but when you do that you’re activating all the cells in that area,” states Weiner. “With optogenetics, we were able to selectively control a specific population of dopamine cells in a part of the brain-reward system. Using this technique, we discovered distinct patterns of dopamine cell activation that seemed to be able to disrupt the alcohol-drinking behavior of the rats.”
Weiner notes the translational value of the study as it gives us better insight into how we might use something like deep-brain stimulation to treat alcoholism. “Doctors are starting to use deep-brain stimulation to treat everything from anxiety to depression, and while it works, there is little scientific understanding behind it”, he says.
Budygin supports the idea of his colleague: “Now we are taking the first steps in this direction… It was impossible before the optogenetic era.” One can now reflect much more on the value of this adjacent tool to better outcomes of the therapeutic interventions in the area of addiction.