Neurons of the body communicate with each other by secreting neurotransmitters. Neurotransmitters are chemicals that bind to receptors embedded in the surface of neurons. Once a neurotransmitter binds to a receptor, it stimulates an electrical impulse that ultimately stimulates the secretion of neurotransmitters. Serotonin is a neurotransmitter that mediates certain functions when it binds to serotonin receptors, according to the University of Washington's Neuroscience For Kids website.
Mood
Serotonin is a neurotransmitter in the nervous system that fulfills its function by attaching onto serotonin receptors. According to an article on the newsroom site for the Washington University in St. Louis, drugs that treat depression increase the amount of serotonin in the nervous system, making more serotonin available to attach to the receptors. But a lack of serotonin might not underlie the cause of depression. Two theories are proposed. The first theory states that the number of serotonin receptors might be the issue. Studies demonstrate that depressive episodes are linked to a decreased number of serotonin receptors, in addition to a smaller hippocampus, an area of the brain linked to emotions and memory. The second theory states that the cause of depression might be similar to the cause of type 2 diabetes, a disease where the receptors don't function correctly.
Anxiety is also associated with decreased serotonin receptor activation, in addition to norepinephrine receptor activation. Anxiety is characterized by restlessness, worry, impaired concentration, irritability, muscle tension and difficulties with sleep. Drugs that increase the concentration of serotonin decrease the feeling of anxiety, according to the U.S. surgeon general.
Intestinal Function
Serotonin is more associated with the central nervous system. However, a high concentration of serotonin receptors are in the intestine and they play a role in intestinal function. Serotonin receptors and serotonin itself increases intestinal motility, secretion and sensation, according to a published experiment by Dr. Meagan Costedio and colleagues in the journal Diseases of the Colon and Rectum. Drugs to treat gastrointestinal disorders, such as constipation, target the serotonin receptors to stimulate intestinal motility. Serotonin receptor dysfunction is also linked to other intestinal disorders, such as inflammatory bowel disease and irritable bowel syndrome.
Other
Obsessive compulsive disorder is a common mental disorder characterized by the compulsion to perform repetitive tasks. If the compulsion is forcibly suppressed, severe anxiety ensues. OCD is linked to serotonin receptor dysfunction. Physicians have observed that OCD symptoms reduce in response to drug treatment using selective serotonin reuptake inhibitors, or SSRIs. SSRIs increase the concentration of serotonin in the nervous system, according to the Stanford School of Medicine.
References
- University of Washington: Neurotransmitters and Neuroactive Peptides
- Washington University, St. Louis: Low serotonin-receptor levels linked to depression
- Surgeon General: Etiology of Anxiety Disorders
- "Diseases of the Colon and Rectum"; Meagan Costedio, Neil Hyman and Gary Mawe; 2007
- Stanford School of Medicine: Understanding Obsessive-Compulsive and Related Disorders
