Dopamine and Serotonin Systems and Disorder

Doctor Randy Blakely discusses the role of the dopamine and serotonin systems in a number of clinical disorders.

Work in the field now is beginning to reveal that the neurochemistry of the brain, particularly studies looking at the actions of metabolic hormones like insulin and other endocrine hormones, can influence the availability of these transporter proteins. It makes some sense; you probably know that the dopamine transporter is a major target for drugs of abuse, like cocaine, and that the dopamine system – one component of the dopamine system – is involved in reward mechanisms and reinforcement. Well, one of the major reinforcements that we have is eating, and eating food makes us feel good. It doesn’t make us feel good just because we have food in our stomachs; it makes us feel good because our brain has received signals that tell us that we now have had enough to eat, or we’ve eaten good food. The brain and the periphery communicate, and that leaves open the possibility that, perhaps, certain disorders that are linked to, let’s say, inappropriate diet or metabolism, could influence the way the dopamine system is working and the dopamine transporter is working. You could make a similar case for serotonin; dietary control of serotonin systems in the brain has been something that has been known for a long time. In fact, clinicians use tryptophan, an amino acid; they deplete tryptophan in patients who have, say, a mood disorder like depression, and they can cause remission of the depression, they can cause the depression to come back, simply by taking away this amino acid in these patients. That’s a major lesson, and there are others that we’ve come across recently. For example, if you have the indications of an infection or an inflammation in the periphery, your brain’s serotonin system will respond. It may be part of a mood change that occurs during things like an inflammatory disorder or the flu. So, our brain is very tightly connected with the rest of our bodies, and what we do to protect our health, our nutrition state, our social behavior, our position in society and in the world, does influence these critical neurotransmitters in the brain.