Overactivity of protein kinase C (PKC), an enzyme that is implicated in bipolar disorder and schizophrenia, markedly impairs higher brain functions in animals, according to a Yale study published Oct. 29 in Science. The research adds to mounting evidence that excessive activity of PKC may underlie the distractibility, impaired judgment, impulsivity, and disturbed thinking seen in bipolar disorder (also known as manic depressive illness), and in schizophrenia. The study also shows that exposure to mild stress can activate PKC, which may lead to worsening of symptoms in patients with these disorders. The findings may explain how upsetting events in the environment can lead to deterioration in higher brain function, and why patients with schizophrenia or bipolar disorder may be particularly susceptible to stress-induced dysfunction. PKC inhibitors may be useful in treating these illnesses, according to Amy Arnsten, associate professor, Department of Neurobiology at Yale School of Medicine and senior author of the study.
