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Is Dopamine Really the ‘Feel-Good’ Hormone?

Stuti Jain | April 10, 2023

It is well-known that dopamine play a key role in allowing us to feel pleasure and satisfaction. However, the Calipari lab revealed that dopamine was more than that. Dr. Erin Calipari is an Assistant Professor of Pharmacology and Molecular Physiology and Biophysics here at Vanderbilt. She has had a long standing interest in pharmacology and how cells function and signal. Dr. Calipari did her undergraduate studies at the University of Massachusetts, where she began studying drug addiction and became interested in how drugs change the brain because they “hijack pathways in our brains and make them work differently, sometimes more or less efficiently.” She came to Vanderbilt to pursue this line of research and now her lab mostly studies how taking drugs changes the way the brain works normally. Half of her lab focuses on how the dopamine system works and what it does, and the other half strives to understand what drug usage does to the dopamine system and what that means for patients recovering from substance use disorder. 

Dopamine’s role, as we understand it now, is making us feel pleasure or satisfaction. When you feel good about something, it is usually because there was a surge of dopamine in your brain. However, the research done by the Calipari lab has worked to dispel the belief that dopamine is only involved in the reward system by showing that it is actually expressed in response to both stressful and pleasurable stimuli. Now, their newest research has shown that dopamine signaling plays a very important role in novelty-based learning. 

What exactly is novelty-based learning, and why is it so important? 

Dr. Calipari explains that, “the definition of novelty is when something is new to us. Something you’ve never seen before, you pay attention to that. And so, novelty actually plays a really big role in learning new things. A good example is how we learn to associate things in our environment with outcomes. If we put our hand on a hot stove, we learned to not do that again because we learned that the stove is hot. But, what can happen is if you are in an environment where you experience the same thing a lot of times, you actually learn to ignore things that are not really relevant. So, they are no longer novel and dont have value to you, leading to you ignoring them. Understanding novelty is really important for how we navigate our environment: 

we pay attention to novel things, and we say, is this important? And if the answer is yes, we learn about it. If the answer is no, we ignore it. It’s actually a really important way for us to adaptively navigate our environment in a way that helps us learn things quickly and very efficiently.” 

What data was collected and how? 

Dr. Calipari and her colleagues used modified proteins as their primary instrument to understand the role of dopamine. These proteins were modified so that when dopamine interacted with them, the protein emitted a light, and these proteins could be expressed anywhere. So, Calipari chose to express these proteins in the brain, allowing them to record dopamine by tracking these flashes of light. With this, they could look at how dopamine was changing in organisms as they are navigating an environment. They looked for if novel things caused dopamine to be released, and what happened to dopamine release as things became less novel. 

What did they find and what are the implications? 

They found that for animals to learn things really quickly, they needed this novelty-elicited dopamine release. The reason that this finding is so important is because deficits in or too much dopamine release are hallmarks of almost every neuropsychiatric disorder including depression, schizophrenia, and bipolar disorder. In order to help these patients whose disorders are characterized by dysfunction in the system, the mechanics of the system has to be understood. 

What’s next? 

They are now working on building on these newest findings by trying to see if there are sex differences, how those differences work, and if that is important for our conceptualization of how the brain works and disease. To do this, they are going to look at how sex hormones such as estradiol and progesterone interact with and cause the dopamine system to change. Calipari feels this an extremely important line of research to pursue because “we basically supplement women with hormones through oral contraceptives all the time. And the question is, what does it do to the system? How does that change how we learn? Is that something we should be looking at?” 

The Calipari Lab is paving the way for research that has huge implications for drug development. Efficacious treatments that work in both men and women require an understanding of how learning differs between the sexes, and that is exactly what Dr. Calipari has set out to figure out. 

Works Cited 

Jain, Stuti. “Dr. Erin Calipari Interview .” 26 Feb. 2023.