Mice May Provide Important Clues for OCD Disorder
Great strides have taken place in the research area of obsessive-compulsive disorder over the past three years, and there is hope that better treatments for humans suffering from this disorder may soon be in place, and it is mice that are providing important clues to what may cause OCD.
The key issue behind OCD research is to find treatment and relief for those humans suffering from this debilitating psychiatric condition which affects about two percent of the world’s population. OCD is one of the most common psychiatric disorders in the world. It is marked by persistent intrusive thoughts (the ...view middle of the document...
This discovery is a huge step in discovering what possibly causes OCD in humans. Dr. Guoping Feng, who led the team of international researchers at Duke, is a molecular geneticist and he comments, "The mice that could not produce this protein exhibited behaviours similar to that of humans with OCD, a compulsive action coupled with increased anxiety. The mice clearly did things that looked like OCD" (Duke).
In their further experiments, the Duke team focused on a portion of the brain known as the striatum, an area that controls the planning and execution of movement, as well as other cognitive functions. It is in many ways "the decider." In normal brains, a protein known as SAPAP3 is crucial for nerve signals to travel from one nerve cell to another across the synapse, the gap between the cells. This protein is important for allowing messages to cross synapses, and it is produced at high levels in the cells that make up the striatum. When the Duke scientists looked closely at the brain cells of the mutant mice, they found that there were defects in the synapses.
The Duke scientists then gave injections to the mice that returned the missing protein into the striatum of the brains of the mutant mice. When the synaptic defects were repaired, their OCD-like behaviours subsided. This is the first scientific evidence that a synaptic defect in the striatum causes OCD-like behaviours.
The researchers also found that a class of drugs known as “selective serotonin reuptake inhibitors (SSRI)” reduced the anxiety levels and suppressed the over-grooming in the mutant mice. This further suggested to the researches that what they observed in mice may also be compared to human OCD. Serotonin, like SAPAP3, is one of many neurotransmitters, chemicals involved in nerve cell communication. While SSRIs are the most commonly prescribed drug for humans with OCD, they are only effective for about half the patients, suggesting to these researchers that many pathways involving different neurotransmitters are likely involved. As a result, Dr. Feng and his group of researchers at Duke are currently looking for additional gene variations that may affect how nerve signals cross synapses, and they are also beginning studies to determine if the gene mutant they discovered in mice plays a role in humans with OCD.
In the meantime, Researchers at the Ansary Stem Cell Institute and the Department of Psychiatry at Weill Cornell Medical College discovered that mice missing a single gene developed repetitive obsessive-compulsive-like behaviours also. These researchers were working with genetically altered mice, which behaved much like people with a certain type of obsessive-compulsive disorder (OCD). Again, this was another “accidental discovery”. The researchers were originally examining what the role of a gene called Slitrk5, had to blood stem and vascular cells. They had disabled the Slitrk5 gene in the mice they were studying and observed OCD like...