Prescription medication usually used to treat Parkinson’s disease has also been found to treat the side affects of depression, according to research done in the psychology department at the University of Connecticut.
Parkinson’s and depression have overlapping symptoms and some neurochemical overlap with the neurotransmitter dopamine, John Salamone, psychology professor and behavioral neuroscience division head, said.
“Both disorders can result in motor slowing, longer reaction times, slower speech,” Salamone said. “I have been working on the hypothesis that some of the psychomotor and motivational symptoms of depression have a dopaminergic component.”
Deprenyl, a drug traditionally used to treat Parkinson’s, increases the amount of extracellular dopamine available. However, Salamone said he had seen papers reporting that MAO-B inhibitors, such as Deprenyl, could be used to treat depression.
“We were already studying this type of drug in our studies related to Parkinsonism, I decided to start using it in our depression related models,” Salamone said.
Deprenyl increases dopamine by preventing enzymes from breaking down which leads to an increase in dopamine and an attenuation of the symptoms of Parkinson’s, Salamone said.
“On the other hand, past studies have shown that the motivational symptoms of depression are caused by a decrease in dopamine. This is why administration of Deprenyl could help by increasing the extracellular dopamine behavior and attenuate the effects of dopamine depletion,” Salamone said.
However, Salamone said that in comparison to other antidepressants, the effectiveness of Deprenyl depends on the depressive symptoms.
Salamone worked with Shanicka Reynolds, an eighth-semester psychology major and neuroscience minor, to focus on the effectiveness of Deprenyl on depression using a rat model.
Rats, Reynolds said, are genetically similar to humans and past pre-clinical research in depression has successfully used rats to simulate depression as seen in humans,
Rats were given this drug and were tested to see if it would increase effort-related behavior since dopamine has been supported from various past studies to increase effort-related behavior, Reynolds said. The rats were tested in an operant chamber where they had to press a lever to receive high reward food, or consume the freely available, less desirable lab chow which required no effort to achieve.
“It was found that when rats were administered Deprenyl they would work harder for the more desirable pellets and that this was due to an increase of dopamine in the area of the brain called the nucleus accumbens,” Reynolds said. “The data collected from this experiment supports the use of Deprenyl as a treatment method for motivational deficits of depression.”
Reynolds said John and Valerie Rowe Foundation and JDS from NIMH funded her for her research.
“I have learned a great deal from my time at the lab. Along with the technical skills such as surgical procedures, I learned how to craft and conduct a research study, how to ask questions that will lead to more in-depth analyses of data, and how to present complex findings to a wide variety of audience member. The lessons I have learned from this lab are invaluable and will become crucial in my pursuit of higher education,” Reynolds said.