Serotonin: A Classic Neurotransmitter Linked With Many Disorders

Serotonin: A Classic Neurotransmitter Linked with Many Disorders

Serotonin has a range of influences on the neurological and physiological function of the body. It has a significant influence on sensitivity to pain, emotionality, and a behavioral response to positive and negative consequences. Serotonin, along with other major neurotransmitters, is also linked with psychotic disorders such as schizophrenia. Serotonin, or HT-5, also has an effect on sleep, eating patterns, and thermoregulation (Meyer et al., 2005). These seem to contribute to depressive symptoms in animals with depleted stores of 5-H. There are now 14 discernable types of serotonin receptor subtypes. Subtypes 2B, 2C, 4, and 6 have all been linked with depression and anxiety (Tohda et al., 2006). Recent research shows that altering 5-HT2CR mRNA to track the origin of depressive diseases may reveal conclusive information about the origin of neurochemical imbalances. (Tohda et al., 2006) There are different approaches to raise serotonin levels in the brain to normal levels. The most commonly prescribed antidepressants are classified as selective serotonin reuptake inhibitors or SSRIs. SSRIs regulate the serotonin transporter, SERT, which slows the reuptake of the neurotransmitter into the presynpatic terminals. While new, more effective drugs with fewer side effects are being deliberated there have been newer ways to attempt to regulate serotonin imbalances. A recent discovery of small interfering RNA molecules may drastically change the treatment of depression and all other neurological diseases. Specially designed siRNA can be used to alter mRNA which will alter the translated protein. This process can be used to silence or increase the potency of its targeted protein (Thakker et al., 2006).

Daniel Hoyer, Ph.D. is a highly published scientist often involved in research concerning the neurotransmitter serotonin. In two recent experiments Daniel Hoyer has dealt with the efficacy of treatment for imbalances of serotonin levels using the new technique of siRNA-mediated knockdown versus the traditional SSRI citalopram. SERTs are ultimately targeted by the siRNA through a chain of events. The siRNA cuts out specific parts of the mRNA and the mRNA will travel into the cytoplasm and attach to a free ribosome. This altered mRNA will cause an error in translation, which will then create non-functioning SERTs (Thakker et al., 2005). Future experiments may also lead to new information on how infusions into the dorsal third ventricle can knockdown gene expression in neural regions as far as the prefrontal cortex. Hoyer is using a new technology in a novel way; this technique is on the cutting edge of technology.

In Hoyer's second recent experiment he tested the affinity for iloperidone for different norepinephrine, dopamine, and serotonin receptors. While not quite using cutting edge technology, this experiment shows how