Subsequently, they treated half of them using systemic, low-dose injections of the drug Amisulpride, which is known to increase dopamine transmission. In their experiments, Lamontagne and his colleagues exposed 48 male rats to stressful stimuli for a period of three weeks. "In our recent work, we completed two major projects to address this question." "A logical hypothesis derived from this finding was that we could rescue stress-induced reward dysfunction by enhancing dopamine signaling, but that hadn't been empirically tested," Lamontagne explained. Their new study was inspired by one of their previous papers, where they tested rodents on a probabilistic reward task and found that chronic stress impaired their reward learning, while amphetamine, which potentiates dopamine transmission, improved it. The main objective of the recent work by Lamontagne and his colleagues was to examine the effects of dopamine modulation on stress-induced motivational deficits in an animal model, specifically on rodents.
"Current first-line drug treatments for depression target the serotonin system, but these are largely ineffective in treating anhedonia." Lamontagne, Ph.D., one of the researchers who carried out the study, told Medical Xpress. "There are very few effective remedies for anhedonia, which is a debilitating condition that involves deficient motivation to pursue rewarding activities," Steven J. Their findings, published in Springer Link's Cognitive, Affective, & Behavioral Neuroscience journal, suggest that the modulation of dopamine could help to reverse stress-induced anhedonia and reward dysfunctions.
Researchers at Queen's University have recently carried out a study on rats, exploring the possibility that drugs targeting dopamine receptors could be better suited for the treatment of anhedonia than those targeting serotonin receptors. In other words, while people taking them often feel an improvement in their overall mood, they do not always gain back the motivation to engage in rewarding activities. Existing pharmacological treatments for depression, such as selective serotonin reuptake inhibitors (SSRIs) and other antidepressants, are not always effective for the treatment of anhedonia.