‘Feel-good’ Dopamine hormone increases in response to stress, not just pleasure
Dopamine, known as the ‘feel-good’ hormone, does not only increase in response to pleasure, but also to stress, a new study finds.
The study, conducted by researchers from Vanderbilt University, puts a lot of what was previously known about the happiness hormone in question.
The researchers have said that the new discovery may lead to a complete re-think of how doctors look at disorders and neurological conditions.
“In the press, dopamine is often referred to as a ‘pleasure molecule’ or a ‘reward molecule,’” assistant professor of pharmacology at the university Erin Calipari was quoted as saying in a statement.
“In the scientific community, research has helped us understand that dopamine’s role in learning and memory is more complex than that, but we did not have a complete and accurate theory that could explain what dopamine actually does in the brain,” she added.
Dopamine increased by ‘stressful stimuli’
Researchers have said that the reward prediction error theory, which is the current prevailing model, is based on the idea that dopamine signals predictions about when rewards will occur. It suggests that dopamine is a tracker of every error we make when we try to achieve rewards.
The study finds that this theory is only accurate in a subset of learning scenarios by proving that “while rewards increase dopamine, so do stressful stimuli,” Calipari said.
“We then go on to show that dopamine is not a reward molecule at all. It instead helps encode information about all types of important and relevant events and drive adaptive behavior – regardless of whether it is positive or negative,” she said.
In collaboration with professor and vice chair of biochemistry and molecular medicine at University of California Davis Lin Tian, the team used cutting-edge technology to study an unprecedented diversity of neurobehavioral processes pertaining to the release of dopamine.
They then used machine learning and computational modeling to analyze the data, along with optogenetic manipulations using light to control the activity of genetically modified neurons, finding a novel computational model of behavior which shows an “accurate predication of the behavioral impact of optogenetic perturbations of dopamine release.”
According to Calipari, the study’s findings “replace our current understanding with a formalized theory and calls for revision of textbook facts regarding dopamine in the central nervous system.”
Rethinking Parkinson’s disease medication, drug abuse, anxiety, depression
The team’s findings have changed the way dopamine is understood. It “rewrite[s] facts about dopamine, including what it encodes within the brain and how it drives behavior,” said Calipari.
“This is incredibly important as dopamine is dysregulated in Parkinson’s disease and in nearly every psychiatric disease: addiction, anxiety and depression, schizophrenia and others,” the statement read.
Gaining a better understanding what these dopamine deficits mean will be a critical part of understanding symptoms of patients and in developing better evidence-based treatments for them.
“Most of our understanding of addiction neurobiology centers around dopamine and the dopaminergic network, as many therapeutic approaches that aim to treat addiction target dopamine. However, altering dopamine without having a full understanding of what dopamine actually does may lead to many unforeseen side effects, and more importantly, failed treatment strategies,” said Calipari.
“This new knowledge about what dopamine actually does will affect many fields outside neuroscience and have a strong impact on human lives and health outcomes.”