Enzyme Mutation May Trigger Certain Psychiatric Diseases

This article originally appeared on Pharmacy Times.

New research suggests psychiatric diseases that affect a patient’s ability to appropriately respond to stimuli may be triggered by the misplacement of an enzyme in the pathway within neurons, according to a study published by Proceedings of the National Academy of Science.

These inappropriate responses include the high and low intensity feelings experienced with bipolar disorder, the impulsiveness associated with attention deficit hyperactive disorder (ADHD), and the overwhelming desire to harm oneself in patients who are suicidal, according to the study authors.

Researchers examined neurons that are involved in sending specialized nerve impulses to the area of the brain stem responsible for reacting to stimuli, the medullary reticular nucleus gigantocelluraris (NGC). The researchers identified the neural pathways, known as messenger ribonucleic acid (mRNA), of these nerve impulses.

Researchers noted the presence of an unusual enzyme in the mRNA: endothelial nitric oxide synthase (eNOS), which is typically only found in blood vessels. Two experiments were conducted on mice to examine the association between the out-of-place eNOS in the NGC cells and inappropriate reactionary behavior.

"Discovering that eNOS was in neurons was quite unexpected, and led to further studying when and how the eNOS within neurons is activated, and how such activation manifests in the body," said senior researcher Joel N.H. Stern, PhD.

The first experiment sought to determine when eNOS is most active. The enzymes natural production of nitric oxide enabled researchers to measure its activity level by monitoring oxidation in the cells, according to the study.

While eNOS was not particularly active when the mice were in familiar environments, such as their home cage, the researchers found that eNOS significantly increased during and after exposure to new environments.

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